Apparatus to increase transferspeed of semiconductor devices with micro-adjustment

ABSTRACT

An apparatus for executing a direct transfer of a semiconductor device die from a first substrate to a second substrate. The apparatus includes a first substrate conveyance mechanism movable in two axes. A micro-adjustment mechanism is coupled with the first substrate conveyance mechanism and is configured to hold the first substrate and to make positional adjustments on a scale smaller than positional adjustments caused by the first substrate conveyance mechanism. The micro-adjustment mechanism includes a micro-adjustment actuator having a distal end and a first substrate holder frame that is movable via contact with the distal end of the micro-adjustment actuator. A second frame is configured to secure the second substrate such that a transfer surface is disposed facing the semiconductor device die disposed on a surface of the first substrate. A transfer mechanism is configured to press the semiconductor device die into contact with the transfer surface of the substrate.

CROSS REFERENCE TO RELATED PATENT APPLICATIONS

This application incorporates by reference U.S. patent application Ser.No. 14/939,896, filed on Nov. 12, 2014, entitled “Apparatus for Transferof Semiconductor Devices,” now issued as U.S. Pat. No. 9,633,883; U.S.patent application Ser. No. 15/343,055, filed on Nov. 3, 2016, entitled“Compliant Needle for Direct Transfer of Semiconductor Devices;” U.S.patent application Ser. No. 15/360,471, filed on Nov. 23, 2016, entitled“Top-Side Laser for Direct Transfer of Semiconductor Devices;” U.S.patent application Ser. No. 15/360,645, filed on Nov. 23, 2016, entitled“Pattern Array Direct Transfer Apparatus and Method Therefor;” U.S.patent application Ser. No. 15/409,409, filed on Jan. 18, 2017, entitled“Flexible Support Substrate for Transfer of Semiconductor Devices;” andU.S. patent application Ser. No. 15/987,094, filed on May 12, 2018,entitled “Method and Apparatus for Multiple Direct Transfers ofSemiconductor Devices.

BACKGROUND

Semiconductor devices are electrical components that utilizesemiconductor material, such as silicon, germanium, gallium arsenide,and the like. Semiconductor devices are typically manufactured as singlediscrete devices or as integrated circuits (ICs). Examples of singlediscrete devices include electrically-actuatable elements such aslight-emitting diodes (LEDs), diodes, transistors, resistors,capacitors, fuses, and the like.

The fabrication of semiconductor devices typically involves an intricatemanufacturing process with a myriad of steps. The end-product of thefabrication is a “packaged” semiconductor device. The “packaged”modifier refers to the enclosure and protective features built into thefinal product as well as the interface that enables the device in thepackage to be incorporated into an ultimate circuit.

The conventional fabrication process for semiconductor devices startswith handling a semiconductor wafer. The wafer is diced into a multitudeof “unpackaged” semiconductor devices. The “unpackaged” modifier refersto an unenclosed semiconductor device without protective features.Herein, unpackaged semiconductor devices may be called semiconductordevice die, or just “die” for simplicity. A single semiconductor wafermay be diced to create die of various sizes, so as to form upwards ofmore than 100,000 or even 1,000,000 die from the semiconductor wafer(depending on the starting size of the semiconductor), and each die hasa certain quality. The unpackaged die are then “packaged” via aconventional fabrication process discussed briefly below. The actionsbetween the wafer handling and the packaging may be referred to as “diepreparation.”

In some instances, the die preparation may include sorting the die via a“pick and place process,” whereby diced die are picked up individuallyand sorted into bins. The sorting may be based on the forward voltagecapacity of the die, the average power of the die, and/or the wavelengthof the die.

Typically, the packaging involves mounting a die into a plastic orceramic package (e.g., mold or enclosure). The packaging also includesconnecting the die contacts to pins/wires forinterfacing/interconnecting with ultimate circuitry. The packaging ofthe semiconductor device is typically completed by sealing the die toprotect it from the environment (e.g., dust).

A product manufacturer then places packaged semiconductor devices inproduct circuitry. Due to the packaging, the devices are ready to be“plugged in” to the circuit assembly of the product being manufactured.Additionally, while the packaging of the devices protects them fromelements that might degrade or destroy the devices, the packaged devicesare inherently larger (e.g., in some cases, around 10 times thethickness and 10 times the area, resulting in 100 times the volume) thanthe die found inside the package. Thus, the resulting circuit assemblycannot be any thinner than the packaging of the semiconductor devices.

As mentioned previously, a single semiconductor wafer may be diced tocreate more than 100,000 or even 1,000,000 die from the semiconductorwafer. As such, efficiency is a primary concern when transferringthousands, if not millions, of die. In transferring these die, there areoften parameters of a die transfer that a manufacturer may not havecontrol over for the sake of efficiency and/or speed. For example, if adie is transferred at a relatively high speed, the high speed transferprocess may cause vibrations to travel throughout the semiconductorsubstrate. In other aspects, even when configured to perform transfersat high speed, starting and stopping the conveying mechanism thatlocates the die for transfer can costly in terms of efficiency.Conventional transfer mechanisms and methods do not provide the abilityto control and/or improve these parameters and others without decreasingthe efficiency of the transfer process.

BRIEF DESCRIPTION OF THE DRAWINGS

The Detailed Description is set forth with reference to the accompanyingfigures. In the figures, the left-most digit(s) of a reference numberidentifies the figure in which the reference number first appears. Theuse of the same reference numbers in different figures indicates similaror identical items. Furthermore, the drawings may be considered asproviding an approximate depiction of the relative sizes of theindividual components within individual figures. However, the drawingsare not to scale, and the relative sizes of the individual components,both within individual figures and between the different figures, mayvary from what is depicted. In particular, some of the figures maydepict components as a certain size or shape, while other figures maydepict the same components on a larger scale or differently shaped forthe sake of clarity.

FIG. 1 illustrates an isometric view of an embodiment of a directtransfer apparatus.

FIG. 2A represents a schematic view of an embodiment of a directtransfer apparatus in a pre-transfer position.

FIG. 2B represents a schematic view of an embodiment of a directtransfer apparatus in a transfer position.

FIG. 3 illustrates an embodiment of a shape profile of the end of aneedle of a direct transfer mechanism.

FIG. 4 illustrates an embodiment of a needle actuation stroke profile.

FIG. 5 illustrates a plan view of an embodiment of a support substratehaving a circuit trace thereon.

FIG. 6 illustrates a schematic view of an embodiment of elements of adirect die transfer system.

FIG. 7 illustrates a schematic view of an embodiment of a circuitry pathbetween machine hardware and controllers of a direct die transfersystem.

FIG. 8 illustrates a method of a direct die transfer process accordingto an embodiment of this application.

FIG. 9 illustrates a method of a direct die transfer operation accordingto an embodiment of this application.

FIG. 10 illustrates an embodiment of a direct transfer apparatus andprocess implementing a conveyor system.

FIG. 11A illustrates a schematic view of another embodiment of a directtransfer apparatus in a pre-transfer position.

FIG. 11B illustrates a schematic top view of the support substrateconveyance mechanism post-transfer operation of the embodiment in FIG.11A.

FIG. 12 illustrates a schematic view of another embodiment of a directtransfer apparatus in a pre-transfer position.

FIG. 13 illustrates a schematic view of another embodiment of a directtransfer apparatus in a pre-transfer position.

FIG. 14 illustrates a schematic view of an embodiment of a directtransfer apparatus, in a pre-transfer position, with a micro-adjustmentassembly implemented according to an embodiment of the instantdisclosure.

FIG. 15A illustrates an isometric view of a micro-adjustment assemblyaccording to an embodiment of the instant disclosure.

FIG. 15B illustrates a schematic cross-sectional view of themicro-adjustment assembly of FIG. 15A, according to an embodiment of theinstant disclosure.

FIG. 15C illustrates another schematic cross-sectional view of themicro-adjustment assembly of FIG. 15A, according to an embodiment of theinstant disclosure.

FIG. 16 illustrates a bottom view of a micro-adjustment assembly havingtwo micro-adjustment actuators according to an embodiment of the instantdisclosure.

FIG. 17 illustrates a bottom view of a micro-adjustment assembly havingfour micro-adjustment actuators according to an embodiment of theinstant disclosure.

FIG. 18 illustrates a method for an example process of actuating adirect transfer apparatus according to an embodiment of the instantdisclosure.

FIG. 19A illustrates an isometric view of a 2-axis rail micro-adjustmentassembly having two micro actuators according to an embodiment of theinstant disclosure.

FIG. 19B illustrates a side view of the 2-axis rail micro-adjustmentassembly of FIG. 19A according to an embodiment of the instantdisclosure.

FIG. 19C illustrates a bottom view of the 2-axis rail micro-adjustmentassembly of FIG. 19A according to an embodiment of the instantdisclosure.

FIG. 20 illustrates another method for an example process of performinga direct transfer with an apparatus having a micro-adjustment assemblyaccording to an embodiment of the instant disclosure.

FIG. 21 illustrates a partial schematic view of a direct die transferhead having multiple pins/needles for use with an apparatus having amicro-adjustment assembly according to an embodiment of the instantdisclosure.

DETAILED DESCRIPTION

This disclosure is directed to a machine that directly transfers andaffixes semiconductor device die to a circuit and to the process forachieving the same, as well as to the circuit having die affixed thereto(as the output product). In an embodiment, the machine functions totransfer unpackaged die directly from a substrate such as a “wafer tape”to a support substrate, such as a circuit substrate. The direct transferof unpackaged die may significantly reduce the thickness of an endproduct compared to a similar product produced by conventional means, aswell as the amount of time and/or cost to manufacture the supportsubstrate.

For the purpose of this description, the term “substrate” refers to anysubstance on which, or to which, a process or action occurs. Further,the term “product” refers to the desired output from a process oraction, regardless of the state of completion. Thus, a support substraterefers to any substance on which, or to which, a process or action iscaused to occur for a desired output.

In an embodiment, the machine may secure a support substrate forreceiving “unpackaged” die, such as LEDs, transferred from the wafertape, for example. In an effort to reduce the dimensions of the productsusing the die, the die are very small and thin, for example, a die maybe about 50 microns (μm) thick. Due to the relatively small size of thedie, the machine includes components that function to precisely alignboth the wafer tape carrying the die and the support substrate to ensureaccurate placement and/or avoid product material waste. In anembodiment, the components that align the support substrate and the dieon the wafer tape may include a set of frames in which the wafer tapeand the support substrate are secured respectively and conveyedindividually to a position of alignment such that a specific die on thewafer tape is transferred to a specific spot on the support substrate.

The frame that conveys the support substrate may travel in variousdirections, including in-plane horizontal, vertical, and/or rotationaldirections for various axes of alignment, or even out-of-planedirections that would permit transfer to a curved surface. The framethat conveys the wafer tape may travel in various directions also. Asystem of gears, tracks, motors, and/or other elements may be used tosecure and convey the frames carrying the support substrate and thewafer tape respectively to align the support substrate with the wafertape in order to place a die on the correct position of the supportsubstrate. Each frame system may also be moved to an extraction positionin order to facilitate extraction of the wafer tape and the supportsubstrate upon completion of the transfer process. It is also to beappreciated that any or all of the first substrate, second substrate,and transfer mechanism may be movable with respect to each other tofacilitate the most efficient alignment of components based on theparticular embodiment.

In some aspects, the components that align the support substrate and thedie on the wafer tape include one or more adjustment mechanisms thatconvey the wafer tape in small distances (e.g., 5 microns to 50 microns,or 1 micron to 1000 microns, or 0.5 micron to 5000 microns, etc.) tofine-adjust the desired location of the transfer die transfer locationto die transfer location. These small conveyances (hereaftermicro-adjustments) can counteract locational inaccuracies of the framethat conveys the wafer tape due to vibration caused by starting andstopping conveyance of the frames (coarse adjustments of the conveyancemechanism(s)) in rapid succession. The inertial vibration noise can varydepending on velocity, unit mass, deceleration, etc. A micro-adjustmentoccurs rapidly (e.g., about 0.5 ms from start to end of themicro-adjustment) to counteract the vibration prior to die transfer.Additionally, after conveying the tape to a transfer location andtransferring of the die, subsequent micro adjustments may be made toalign additional transfer locations and transfer die prior to the nextcoarse adjustment.

In an embodiment, the machine further includes a transfer mechanism fortransferring the die directly from the wafer tape to the supportsubstrate without “packaging” the die. The transfer mechanism may bedisposed vertically above the wafer tape so as to press down on the dievia the wafer tape toward the support substrate. This process ofpressing down on the die may cause the die to peel off of the wafertape, starting at the sides of the die until the die separate from thewafer tape to be attached to the support substrate. That is, by reducingthe adhesion force between the die and the wafer tape, and by increasingthe adhesion force between the die and the support substrate, the diemay be transferred.

In some embodiments, the transfer mechanism may include an elongatedrod, such as a pin or needle that may be cyclically actuated against thewafer tape to push the wafer tape from a top side. Additionally, and/oralternatively, the transfer mechanism may include a plurality of needlesthat may be individually actuated against the wafer tape. The needle, orneedles, may be sized so as to be no wider than a width of the die beingtransferred. Although in other instances, the width of the needle may bewider than a width of the die, or any other dimension. When the end ofthe needle contacts the wafer tape, the wafer tape may experience alocal deflection at the area between the die and the wafer tape.Inasmuch as the deflection is highly localized and rapidly performed,the portion of the wafer tape that does not receive pressure from theneedle may begin to flex away from the surface of the die. This partialseparation may thus cause the die to lose sufficient contact with thewafer tape, so as to be released from the wafer tape. Moreover, in anembodiment, the deflection of the wafer tape may be so minimal, as tomaintain an entirety of the surface area of the die in contact with thewafer tape, while still causing the opposing surface of the die toextend beyond a plane of extension of the corresponding surface of theadjacent die to avoid unintentional transfer of the adjacent die.

Alternatively, or additionally, the machine may further include a fixingmechanism for affixing the separated, “unpackaged” die to the supportsubstrate. In an embodiment, the support substrate may have thereon acircuit trace to which the die are transferred and affixed. The fixingmechanism may include a device that emits energy, such as a laser, tomelt/soften the material of the circuit trace on the support substrate.Moreover, in an embodiment, the laser may be used to activate/harden thematerial of the circuit trace. Thus, the fixing mechanism may beactuated before, and/or after the die is in contact with the material ofthe circuit trace. Accordingly, upon actuation of the transfer mechanismto release a die onto the support substrate, the energy emitting devicemay also be activated so as to prepare the trace material to receive thedie. The activation of the energy emitting device may further enhancethe release and capture of the die from the wafer tape so as to beginformation of a semiconductor product on the support substrate.

In some embodiments, as the frame holding the wafer tape is conveyedfrom location to location, the conveyance mechanism holding the waferframe may move to the transfer location, and after coming to an abruptstop, perform a micro-adjustment that fine-tunes the transfer locationand/or removes system vibrations. The system then transfers the die viathe fixing mechanism as described above.

In other embodiments, the conveyance mechanism may not come to acomplete stop before transfer of the die from the wafer tape to thesupport substrate. In some aspects, the system may vary the velocity ofconveyance mechanism as it approaches the desired transfer location,while in other aspects the conveyance mechanism may maintain a constantvelocity as it passes though desired transfer locations. At acalculatable moment in time with respect to the transfer position, thesystem may actuate the micro-actuation mechanism in the one or more axesof travel, at 180 degrees from the direction of travel. The velocity ofthe micro-actuation matches the velocity of travel of the frame suchthat the position of the die being transferred is motionless withrespect to the target position on the support. That is, the relativevelocity of the transfer elements (e.g., conveyance mechanisms andtransfer mechanism) becomes zero because of the opposite-directionactuation of the micro-adjustment mechanism. At the instant that the dieis motionless with respect to the target position, the transfermechanism pushes the die off of the wafer tape into position on thesubstrate support, and the fixing mechanism fixes the die as describedherein. Because the conveyance mechanism never completely stops,manufacturing efficiencies are gained from time saved waiting for systemvibrations of the coarse conveyance mechanisms to settle at eachtransfer location.

First Example Embodiment of a Direct Transfer Apparatus

FIG. 1 illustrates an embodiment of an apparatus 100 that may be used todirectly transfer unpackaged semiconductor components (or “die”) from awafer tape to a support substrate. The wafer tape may also be referredto herein as the semiconductor device die substrate, or simply a diesubstrate. The apparatus 100 may include a support substrate conveyancemechanism 102 and a wafer tape conveyance mechanism 104. Each of thesupport substrate conveyance mechanism 102 and the wafer tape conveyancemechanism 104 may include a frame system or other means to secure therespective substrates to be conveyed to desired alignment positions withrespect to each other. The apparatus 100 may further include a transfermechanism 106, which, as shown, may be disposed vertically above thewafer tape conveyance mechanism 104. In an embodiment, the transfermechanism 106 may be located so as to nearly contact the wafer tape.Additionally, the apparatus 100 may include a fixing mechanism 108. Thefixing mechanism 108 may be disposed vertically beneath the supportsubstrate conveyance mechanism 102 in alignment with the transfermechanism 106 at a transfer position, where a die may be placed on thesupport substrate. As discussed below, FIGS. 2A and 2B illustrateexample details of the apparatus 100.

Inasmuch as FIGS. 2A and 2B depict different stages of the transferoperation, while referring to the same elements and features ofapparatus 200, the following discussion of specific features may referinterchangeably to either or both of FIGS. 2A and 2B, except whereexplicitly indicated. In particular, FIGS. 2A and 2B illustrate anembodiment of an apparatus 200, including a support substrate conveyancemechanism 202, a wafer tape conveyance mechanism 204, a transfermechanism 206, and a fixing mechanism 208. The support substrateconveyance mechanism 202 may be disposed adjacent to the wafer tapeconveyance mechanism 204. For example, as illustrated, the supportsubstrate conveyance mechanism 202 may extend in a substantiallyhorizontal direction and may be disposed vertically beneath the wafertape conveyance mechanism 204 so as to take advantage of any effect thatgravity may have in the transfer process. Alternatively, the supportsubstrate conveyance mechanism 202 may be oriented so as to extendtransversely to a horizontal plane.

During a transfer operation, the conveyance mechanisms 202, 204 may bepositioned such that a space between a surface of a support substratecarried by the support substrate conveyance mechanism 202 and a surfaceof a wafer tape carried by the wafer tape conveyance mechanism 204 maybe more or less than 1 mm, depending on various other aspects of theapparatus 200, including the amount of deflection that occurs bycomponents during the transfer operation, as described herein below. Inan embodiment, the respective opposing surfaces of the wafer tape andthe support substrate may be the most prominent structures in comparisonto the supporting structures of the conveyance mechanisms 202, 204. Thatis, in order to avoid a collision between components of the machine andproducts thereon, which might be caused by movable parts (e.g., theconveyance mechanisms 202, 204), a distance between the respectivesurfaces of the wafer tape and support substrate may be less than adistance between either of the surfaces and any other opposingstructural component.

As depicted, and in an embodiment, the transfer mechanism 206 may bedisposed vertically above the wafer tape conveyance mechanism 204, andthe fixing mechanism 208 may be disposed vertically beneath the supportsubstrate conveyance mechanism 202. It is contemplated that in someembodiments, one or both of the transfer mechanism 206 and the fixingmechanism 208 may be oriented in different positions than the positionsillustrated in FIGS. 2A and 2B. For example, the transfer mechanism 206may be disposed so as to extend at an acute angle with respect to ahorizontal plane. In another embodiment, the fixing mechanism 208 may beoriented to emit energy during the transfer process from the samedirection of actuation as the transfer mechanism 206, or alternatively,from any orientation and position from which the fixing mechanism 208 isable to participate in the transfer process.

The support substrate conveyance mechanism 202 may be used to secure asupport substrate 210. Herein, the term “support substrate” may include,but is not limited to: a wafer tape (for example, to presort the die andcreate sorted die sheets for future use); a paper or polymer substrateformed as a sheet or other non-planar shape, where thepolymer—translucent or otherwise—may be selected from any suitablepolymers, including, but not limited to, a silicone, an acrylic, apolyester, a polycarbonate, etc.; a circuit board (such as a printedcircuit board (PCB)); a string or thread circuit, which may include apair of conductive wires or “threads” extending in parallel; and a clothmaterial of cotton, nylon, rayon, leather, etc. The choice of materialof the support substrate may include durable materials, flexiblematerials, rigid materials, and other materials with which the transferprocess is successful and which maintain suitability for the end use ofthe support substrate. The support substrate 210 may be formed solely orat least partially of conductive material such that the supportsubstrate 210 acts as a conductive circuit for forming a product. Thepotential types of support substrate may further include items, such asglass bottles, vehicle windows, or sheets of glass.

In an embodiment as depicted in FIGS. 2A and 2B, the support substrate210 may include a circuit trace 212 disposed thereon. The circuit trace212, as depicted, may include a pair of adjacent trace lines spacedapart by a trace spacing, or gap so as to accommodate a distance betweenelectrical contact terminals (not shown) on the die being transferred.Thus, the trace spacing, or gap between the adjacent trace lines of thecircuit trace 212 may be sized according to the size of the die beingtransferred to ensure proper connectivity and subsequent activation ofthe die. For example, the circuit trace 212 may have a trace spacing, orgap ranging from about 75 to 200 microns, about 100 to 175 microns, orabout 125 to 150 microns.

The circuit trace 212 may be formed from a conductive ink disposed viascreen printing, inkjet printing, laser printing, manual printing, orother printing means. Further, the circuit trace 212 may be pre-curedand semi-dry or dry to provide additional stability, while still beingactivatable for die conductivity purposes. A wet conductive ink may alsobe used to form the circuit trace 212, or a combination of wet and dryink may be used for the circuit trace 212. Alternatively, oradditionally, the circuit trace 212 may be pre-formed as a wire trace,or photo-etched, or from molten material formed into a circuit patternand subsequently adhered, embedded, or otherwise secured to the supportsubstrate 210.

The material of the circuit trace 212 may include, but is not limitedto, silver, copper, gold, carbon, conductive polymers, etc. In anembodiment, the circuit trace 212 may include a silver-coated copperparticle. A thickness of the circuit trace 212 may vary depending on thetype of material used, the intended function and appropriate strength orflexibility to achieve that function, the energy capacity, the size ofthe LED, etc. For example, a thickness of the circuit trace may rangefrom about 5 microns to 20 microns, from about 7 microns to 15 microns,or from about 10 microns to 12 microns.

Accordingly, in one non-limiting example, the support substrate 210 maybe a flexible, translucent polyester sheet having a desired circuitpattern screen printed thereon using a silver-based conductive inkmaterial to form the circuit trace 212.

The support substrate conveyance mechanism 202 may include a supportsubstrate conveyor frame 214 for securing a support substrate holderframe 216. The structure of the support substrate holder frame 216 mayvary significantly depending on the type and properties (e.g., shape,size, elasticity, etc.) of the support substrate being used. Inasmuch asthe support substrate 210 may be a flexible material, support substrate210 may be held under tension in the support substrate holder frame 216,so as to create a more rigid surface upon which a transfer operation,discussed herein below, is performed. In the above example, the rigiditycreated by the tension in the support substrate 210 may increase theplacement accuracy when transferring components.

In an embodiment, using a durable or more rigid material for the supportsubstrate 210, naturally provides a firm surface for component placementaccuracy. In contrast, when the support substrate 210 is allowed to sag,wrinkles and/or other discontinuities may form in the support substrate210 and interfere with the pre-set pattern of the circuit trace 212, tothe extent that the transfer operation may be unsuccessful.

While the means of holding the support substrate 210 may vary greatly,FIG. 2A illustrates an embodiment of a support substrate holder frame216 including a first portion 216 a having a concave shape and a secondportion 216 b having a convex counter shape that corresponds in shape tothe concave shape. In the depicted example, tension is created for thesupport substrate 210 by inserting an outer perimeter of the supportsubstrate 210 between the first portion 216 a and the second portion 216b to thereby clamp the support substrate 210 tightly.

The support substrate conveyor frame 214 may be conveyed in at leastthree directions—two directions in the horizontal plane and verticallyas well. The conveyance may be accomplished via a system of motors,rails, and gears (none of which are shown). As such, the supportsubstrate holder frame 216 may be conveyed to and held in a specificposition as directed and/or programmed and controlled by a user of theapparatus 200.

The wafer tape conveyance mechanism 204 may be implemented to secure awafer tape 218 having die 220 (i.e., semiconductor device die) thereon.The wafer tape 218 may be conveyed in multiple directions to thespecific transfer positions for the transfer operation via a wafer tapeconveyor frame 222. Similar to the support substrate conveyor frame 214,the wafer tape conveyor frame 222 may include a system of motors, rails,and gears (none of which are shown).

The unpackaged semiconductor die 220 for transfer may be extremelysmall. Indeed, the height of the die 220 may range from 12.5 to 200microns, or from 25 to 100 microns, or from 50 to 80 microns.

Due to the micro size of the die, when the wafer tape 218 has beenconveyed to the appropriate transfer position, a gap spacing between thewafer tape 218 and the support substrate 210 may range from about 0.25mm to 1.50 mm, or about 0.50 mm to 1.25 mm, or about 0.75 mm to 1.00 mm,for example. A minimum gap spacing may depend on factors including: athickness of the die being transferred, a stiffness of the wafer tapeinvolved, an amount of deflection of the wafer tape needed to provideadequate capture and release of the die, a proximity of the adjacentdie, etc. As the distance between the wafer tape 218 and the supportsubstrate 210 decreases, a speed of the transfer operation may alsodecrease due to the reduced cycle time (discussed further herein) of thetransfer operation. Such a decrease in the duration of a transferoperation may therefore increase a rate of die transfers. For example,the die transfer rate may range from about 6-250 die placed per second.

Furthermore, the wafer tape conveyor frame 222 may secure a wafer tapeholder frame 224, which may stretch and hold the wafer tape 218 undertension. As illustrated in FIG. 2A, the wafer tape 218 may be secured inthe wafer tape holder frame 224 via clamping a perimeter of the wafertape 218 between adjacent components of the wafer tape holder frame 224.Such clamping assists in maintaining the tension and stretchedcharacteristic of the wafer tape 218, thereby increasing the successrate of the transfer operation. In view of the varying properties ofdifferent types/brands/qualities of wafer tapes available, a particularwafer tape may be selected for use based on an ability to consistentlyremain at a desired tension during a transfer process. In an embodiment,the needle actuation performance profile (discussed further hereinbelow) may change depending on the tension of the wafer tape 218.

The material used for the wafer tape 218 may include a material havingelastic properties, such as a rubber or silicone, for example.Furthermore, inasmuch as temperature of the environment and the wafertape 218 itself may contribute to potential damage to the wafer tape 218during the transfer process, a material having properties that areresistant to temperature fluctuation may be advantageous. Additionally,in an embodiment, the wafer tape 218 may be stretched slightly so as tocreate a separation or gap between individual die 220 to assist in thetransfer operation. A surface of the wafer tape 218 may include a stickysubstance via which the die 220 may be removably adhered to the wafertape 218.

The die 220 on the wafer tape 218 may include die that were individuallycut from a solid semiconductor wafer and then placed onto the wafer tape218 to secure the die. In such a situation, the die may have beenpre-sorted and explicitly organized on the wafer tape 218, in order, forexample, to assist in the transfer operation. In particular, the die 220may be arranged sequentially as to the expected order of transfer to thesupport substrate 210. Such pre-arrangement of the die 220 on the wafertape 218 may reduce the amount of travel that would otherwise occurbetween the support substrate conveyance mechanism 202 and the wafertape conveyance mechanism 204. Additionally, or alternatively, the dieon the wafer tape 218 may have been pre-sorted to include only diehaving substantially equivalent performance properties. In this case,efficiency of the supply chain may be increased and thus, travel time ofthe wafer tape conveyance mechanism 204 may be reduced to a minimum.

In an embodiment, materials used for the die may include, but is notlimited to, silicon carbide, gallium nitride, a coated silicon oxide,etc. Furthermore, sapphire or silicon may be used as a die as well.Additionally, as indicated above, a “die” may be representative hereinof an electrically actuatable element generally.

In some embodiments, the wafer tape 218 may include die that are notpre-sorted, but rather are formed by simply cutting a semiconductordirectly on wafer tape, and then leaving the die on the wafer tapewithout “picking and placing” to sort the die depending on therespective performance quality of the die. In such a situation, the dieon the wafer tape may be mapped to describe the exact relative locationsof the different quality die. Therefore, in an embodiment, it may beunnecessary to use wafer tape having pre-sorted die. In such a case, theamount of time and travel for the wafer tape conveyance mechanism 204 tomove between particular die for each sequential transfer operation mayincrease. This may be caused in part by the varying quality of the diedispersed within the area of the semiconductor, which means that a dieof a specific quality for the next transfer operation may not beimmediately adjacent to the previously transferred die. Thus, the wafertape conveyance mechanism 204 may move the wafer tape 218 further toalign an appropriate die of a specific quality for transfer than wouldbe necessary for a wafer tape 218 containing die of substantiallyequivalent quality.

In further regard to the die 220 on the wafer tape 218, in anembodiment, a data map of the die 220 may be provided with the wafertape 218. The data map may include a digital file providing informationthat describes the specific quality and location of each die on thewafer tape 218. The data map file may be input into a processing systemin communication with the apparatus 200, whereby the apparatus 200 maybe controlled/programmed to seek the correct die 220 on the wafer tape218 for transfer to the support substrate 210.

A transfer operation is performed, in part, via the transfer mechanism206, which is a die separation device for assisting in separation of diefrom the wafer tape 218. The actuation of the transfer mechanism 206 maycause one or more die 220 to be released from the wafer tape 218 and tobe captured by the support substrate 210. In an embodiment, the transfermechanism 206 may operate by pressing an elongated rod, such as a pin ora needle 226 into a top surface of the wafer tape 218 against a die 220.The needle 226 may be connected to a needle actuator 228. The needleactuator 228 may include a motor connected to the needle 226 to drivethe needle 226 toward the wafer tape 218 at predetermined/programmedtimes.

In view of the function of the needle 226, the needle 226 may include amaterial that is sufficiently durable to withstand repetitive, rapid,minor impacts while minimizing potential harm to the die 220 uponimpact. For example, the needle 226 may include a metal, a ceramic, aplastic, etc. Additionally, a tip of the needle 226 may have aparticular shape profile, which may affect the ability of the needle tofunction repetitively without frequently breaking either the tip ordamaging the wafer tape 218 or the die 220. The profile shape of the tipof the needle is discussed in greater detail below with respect to FIG.3.

In a transfer operation, the needle 226 may be aligned with a die 220,as depicted in FIG. 2A, and the needle actuator may move the needle 226to push against an adjacent side of the wafer tape 218 at a position inwhich the die 220 is aligned on the opposing side of the wafer tape 218,as depicted in FIG. 2B. The pressure from the needle 226 may cause thewafer tape 218 to deflect so as to extend the die 220 to a positioncloser to the support substrate 210 than adjacent die 220, which are notbeing transferred. As indicated above, the amount of deflection may varydepending several factors, such as the thickness of the die and circuittrace. For example, where a die 220 is about 50 microns thick andcircuit trace 212 is about 10 microns thick, an amount of deflection ofthe wafer tape 218 may be about 75 microns. Thus, the die 220 may bepressed via the needle 226 toward the support substrate 210 to theextent that the electrical contact terminals (not shown) of the die areable to bond with the circuit trace 212, at which point, the transferoperation proceeds to completion and the die 220 is released from thewafer tape 218.

To the extent that the transfer process may include a rapidly repeatedset of steps including a cyclical actuation of the needle 226 pressingupon a die 220, a method of the process is described in detail hereinbelow with respect to FIG. 8. Further, the stroke profile of theactuation of the needle 226 (within the context of the transfer process)is discussed in more detail hereafter with respect to FIG. 4.

Turning back to FIGS. 2A and 2B, in an embodiment, the transfermechanism 206 may further include a needle retraction support 230, (alsoknown as a pepper pot). In an embodiment, the support 230 may include astructure having a hollowed space wherein the needle 226 may beaccommodated by passing into the space via an opening 232 in a first endof the support 230. The support 230 may further include at least oneopening 234 on a second opposing end of the support 230. Moreover, thesupport may include multiple perforations near opening 234. The at leastone opening 234 may be sized with respect to a diameter of the needle226 to accommodate passage of the needle 226 therethrough so as to presson the wafer tape 218 during the transfer process.

Additionally, in an embodiment, the support 230 may be disposed adjacentto the upper surface of the wafer tape 218. As such, when the needle 226is retracted from pressing on the wafer tape 218 during a transferoperation, a base surface of the support 230 (having the at least oneopening 234 therein) may come into contact with the upper surface of thewafer tape 218, thereby preventing upward deflection of the wafer tape218. This upward deflection may be caused in the event where the needle226 pierces at least partially into the wafer tape 218, and whileretracting, the wafer tape is stuck to the tip of the needle 226. Thus,the support 230 may reduce the time it takes to move to the next die220. A wall perimeter shape of the support 230 may be cylindrical or anyother shape that may be accommodated in the apparatus 200. Accordingly,the support 230 may be disposed between the needle 226 and an uppersurface of the wafer tape 218.

With respect to the effect of temperature on the integrity of the wafertape 218, it is contemplated that a temperature of support 230 may beadjusted so as to regulate the temperature of the needle 226 and thewafer tape 218, at least near the point of the transfer operation.Accordingly, the temperature of the support 230 may be heated or cooled,and a material of the support 230 may be selected to maximize thermalconductivity. For example, the support 230 may be formed of aluminum, oranother relatively high thermal conductivity metal or comparablematerial, whereby the temperature may be regulated to maintainconsistent results of the transfer operations. In an embodiment, air maybe circulated within the support 230 to assist in regulating thetemperature of a local portion of the wafer tape 218. Additionally, oralternatively, a fiber optic cable 230 a may be inserted into the needleretraction support 230, and may further be against the needle 226 toassist in temperature regulation of the wafer tape 218 and/or the needle226.

As indicated above, fixing mechanism 208 may assist in affixing the die220 to the circuit trace 212 on a surface of the support substrate 210.FIG. 2B illustrates the apparatus 200 in a transfer stage, where the die220 is pushed against the circuit trace 212. In an embodiment, fixingmechanism 208 may include an energy-emitting device 236 including, butnot limited to: a laser, electromagnetic radiation, pressure vibration,ultrasonic welding, etc. In an embodiment, the use of pressure vibrationfor the energy-emitting device 236 may function by emitting a vibratoryenergy force so as to cause disruption of the molecules within thecircuit trace against those of the electrical contact terminals so as toform a bond via the vibratory pressure. Furthermore, in an embodiment,the fixing mechanism 208 may be omitted entirely, and a transfer of oneor more die to a circuit substrate may occur via other means, includingadhesive strength or bonding potential.

In a non-limiting example, as depicted in FIG. 2B, a laser may beimplemented as the energy-emitting device 236. During a transferoperation, laser 236 may be activated to emit a specific wavelength andintensity of light energy directed at the die 220 being transferred. Thewavelength of the light of the laser 236 may be selected specificallybased on the absorption of that wavelength of light with respect to thematerial of the circuit trace 212 without significantly affecting thematerial of the support substrate 210. For example, a laser having anoperational wavelength of 808 nm, and operating at 5 W may be readilyabsorbed by silver, but not by polyester. As such, the laser beam maypass through the substrate of polyester and affect the silver of acircuit trace. Alternatively, the wavelength of laser may match theabsorption of the circuit trace and the material of the substrate. Thefocus area of the laser 236 (indicated by the dashed lines emanatingvertically from the laser 236 in FIG. 2B toward the support substrate210) may be sized according to the size of the LED, such as for example,a 300 micron wide area.

Upon actuation of a predetermined controlled pulse duration of the laser236, the circuit trace 212 may begin to cure (and/or melt or soften) toan extent that a fusing bond may form between the material of thecircuit trace 212 and the electrical contact terminals (not shown) onthe die 220. This bond further assists in separating the unpackaged die220 from the wafer tape 218, as well as simultaneously affixing the die220 to the support substrate 210. Additionally, the laser 236 may causesome heat transfer on the wafer tape 218, thereby reducing adhesion ofthe die 220 to the wafer tape 218 and thus assisting in the transferoperation.

In other instances, die may be released and fixed to the supportsubstrates in many ways, including using a laser having a predeterminedwavelength or a focused light (e.g., IR, UV, broadband/multispectral)for heating/activating circuit traces to thereby cure an epoxy or phasechange bond materials, or for deactivating/releasing a die from wafertape, or for initiating some combination of reactions. Additionally, oralternatively, a specific wavelength laser or light may be used to passthrough one layer of the system and interact with another layer.Furthermore, a vacuum may be implemented to pull a die from the wafertape, and air pressure may be implemented to push the die onto a supportsubstrate, potentially including a rotary head between the die wafertape and the support substrate. In yet another instance, ultrasonicvibration may be combined with pressure to cause the die to bond to thecircuit traces.

Similar to the needle retraction support 230, the fixing mechanism mayalso include a support substrate support 238, which may be disposedbetween the laser 236 and the bottom surface of the support substrate210. The support 238 may include an opening 240 at a base end thereofand an opening 242 at an upper end thereof. For example, the support 238may be formed as a ring or hollow cylinder. The support may furtherinclude structure to secure a lens (not shown) to assist in directingthe laser. The laser 236 emits the light through the openings 240, 242to reach the support substrate 210. Furthermore, the upper end of thesidewalls of the support 238 may be disposed in direct contact with orclosely adjacent to the bottom surface of the support substrate 210.Positioned as such, the support 238 may help to prevent damage fromoccurring to the support substrate 210 during the stroke of the needle226 at the time of a transfer operation. In an embodiment, during thetransfer operation, the portion of the bottom surface of the supportsubstrate 210 that is aligned with the support 238 may contact thesupport 238, which thereby provides resistance against the incomingmotion of the die 220 being pressed by the needle 226. Moreover, thesupport 238 may be movable in a direction of the vertical axis to beable to adjust a height thereof so as to raise and lower support 238 asnecessary, including to a height of the support substrate 210.

In addition to the above features, apparatus 200 may further include afirst sensor 244, from which apparatus 200 receives informationregarding the die 220 on the wafer tape 218. In order to determine whichdie is to be used in the transfer operation, the wafer tape 218 may havea bar code (not shown) or other identifier, which is read or otherwisedetected. The identifier may provide die map data to the apparatus 200via the first sensor 244.

As shown in FIGS. 2A and 2B, the first sensor 244 may be positioned nearthe transfer mechanism 206 (or the needle 226 specifically), spacedapart from the transfer mechanism 206 by a distance d, which may rangefrom about 1-5 inches, so as to enhance the accuracy of locationdetection. In an alternative embodiment, first sensor 244 may bedisposed adjacent the tip of the needle 226 in order to sense the exactposition of the die 220 in real time. During the transfer process, thewafer tape 218 may be punctured and or further stretched over time,which may alter the previously mapped, and thus expected, locations ofthe die 220 on the wafer tape 218. As such, small changes in thestretching of the wafer tape 218 could add up to significant errors inalignment of the die 220 being transferred. Thus, real time sensing maybe implemented to assist in accurate die location.

In an embodiment, the first sensor 244 may be able to identify theprecise location and type of die 220 that is being sensed. Thisinformation may be used to provide instructions to the wafer tapeconveyor frame 222 indicating the exact location to which the wafer tape218 should be conveyed in order to perform the transfer operation.Sensor 244 may be one of many types of sensors, or a combination ofsensor types to better perform multiple functions. Sensor 244 mayinclude but is not limited to: a laser range finder, or an opticalsensor, such as a non-limiting example of a high-definition opticalcamera having micro photography capabilities.

Moreover, in an embodiment, a second sensor 246 may also be included inapparatus 200. The second sensor 246 may be disposed with respect to thesupport substrate 210 so as to detect the precise position of thecircuit trace 212 on the support substrate 210. This information maythen be used to determine any positional adjustment needed to align thesupport substrate 210 between the transfer mechanism 206 and the fixingmechanism 208 so that the next transfer operation occurs in the correctlocation on the circuit trace 212. This information may further berelayed to the apparatus 200 to coordinate conveying the supportsubstrate 210 to a correct position, while simultaneously conveyinginstructions to the wafer tape conveyor frame 222. A variety of sensorsare also contemplated for sensor 246 including optical sensors, such asone non-limiting example of a high-definition optical camera havingmicro photography capabilities.

FIGS. 2A and 2B further illustrate that the first sensor 244, the secondsensor 246, and the laser 236 may be grounded. In an embodiment, thefirst sensor 244, the second sensor 246, and the laser 236 may all begrounded to the same ground (G), or alternatively, to a different ground(G).

Depending on the type of sensor used for the first and second sensors244, 246, the first or second sensors may further be able to test thefunctionality of transferred die. Alternatively, an additional testersensor (not shown) may be incorporated into the structure of apparatus200 to test individual die before removing the support substrate 210from the apparatus 200.

Furthermore, in some examples, multiple independently-actuatable needlesand/or lasers may be implemented in a machine in order to transfer andfix multiple die at a given time. The multiple needles and/or lasers maybe independently movable within a three-dimensional space. Multiple dietransfers may be done synchronously (multiple needles going down at thesame time), or concurrently but not necessarily synchronously (e.g., oneneedle going down while the other is going up, which arrangement maybalance better the components and minimize vibration). Control of themultiple needles and/or lasers may be coordinated to avoid collisionsbetween the plurality of components. Moreover, in other examples, themultiple needles and/or lasers may be arranged in fixed positionsrelative to each other.

Example Needle Tip Profile

As mentioned above, a profile shape of the tip 300 of a needle isdiscussed with respect to FIG. 3, which shows a schematic exampleprofile shape of the tip 300. In an embodiment, the tip 300 may bedefined as the end of the needle, including sidewalls 302 adjoiningtapered portion 304, corner 306, and base end 308, which may extendtransversely to the opposing side of the needle. The specific size andshape of the tip 300 may vary according to factors of the transferprocess such as, for example, the size of the die 220 being transferredand the speed and the impact force, of a transfer operation. Forexample, the angle θ seen in FIG. 3, as measured between a longitudinaldirection of the central axis of the needle and the tapered portion 304may range from about 10 to 15°; the radius r of the corner 306 may rangefrom about 15 to 50+ microns; the width w of the base end 308 may rangefrom about 0 to 100+ microns, where w may be less than or equal to thewidth of the die 220 being transferred; the height h of the taperedportion 304 may range from about 1 to 2 mm, where h may be greater thana distance traveled by needle during a stroke of a transfer operation;and the diameter d of the needle 226 may be approximately 1 mm.

Other needle tip profiles are contemplated and may have differentadvantages depending on various factors associated with the transferoperation. For example, the needle tip 300 may be more blunt to mirrorthe width of the die or more pointed so as to press in a smaller area ofthe wafer tape. In an embodiment, the transfer mechanism 206 mayimplement two or more needles. In such an instance, the two or moreneedles may have a substantially similar needle profile or they may havesubstantially different needle profiles. For example, the transfermechanism 206 may include one or more needles 226 that have a needle tipprofile as described and depicted with regard to FIG. 3. The transfermechanism may further include one or more needles 226 that have asubstantially different needle tip profile (i.e., wider than thedepicted and described needle tip profile or narrower than the depictedand described needle tip profile). In an embodiment, the needle profilemay not include any tapering to a point such that the needle 226includes a constant width along an entire length of the needle 226.

Example Needle Actuation Performance Profile

Illustrated in FIG. 4 is an embodiment of a needle actuation performanceprofile. That is, FIG. 4 depicts an example of the stroke patternperformed during a transfer operation by displaying the height of theneedle tip with respect to the plane of the wafer tape 218 as it varieswith time. As such, the “0” position in FIG. 4 may be the upper surfaceof the wafer tape 218. Further, inasmuch as the idle time of the needleand the ready time of the needle may vary depending on the programmedprocess or the varying duration of time between transferring a first dieand the time it takes to reach a second die for transfer, the dashedlines shown at the idle and ready phases of the stroke pattern indicatethat the time is approximate, but may be longer or shorter in duration.Moreover, it is to be understood that the solid lines shown for use ofthe laser are example times for an embodiment illustrated herewith,however, the actual duration of laser on and off time may vary dependingon the materials used in forming the circuit (such as the materialchoice of the circuit trace), the type of support substrate, the desiredeffect (pre-melting circuit trace, partial bond, complete bond, etc.),the distance of the laser from the bond point (i.e., the upper surfaceof the support substrate), the size of the die being transferred, andthe power/intensity/wavelength of the laser, etc. Accordingly, thefollowing description of the profile shown in FIG. 4 may be an exampleembodiment of a needle profile.

In an embodiment, prior to a transfer operation, a fully retractedneedle tip may be idle at approximately 2000 μm above the surface of thewafer tape. After a varying amount of time, the needle tip may descendrapidly to rest in the ready state at approximately 750 μm above thesurface of the wafer tape. After another undetermined amount of time atthe ready state, the needle tip may descend again to contact the die andpress the wafer tape with the die down to a height of approximately−1000 μm, where at the die may be transferred to the support substrate.The dotted vertical line at the start of the laser on section indicatesthat the laser may come on at some point between the beginning of thedescent from the ready phase and the bottom of the stroke of the needletip. For example, the laser may turn on at approximately 50% of the waythrough the descent. In an embodiment, by turning the laser on early,for example before the needle begins to descend, the circuit trace maybegin to soften prior to contact with the die so as to form a strongerbond, or additionally, the die wafer may be affected or prepared duringthis time. The phase in which the laser turns on may last approximately20 ms (“milliseconds”). At the bottom of the stroke, where the laser ison, that phase may be a bonding phase between the die and the supportsubstrate. This bonding phase may allow the circuit trace to attach tothe die contacts, which stiffens quickly after the laser is turned off.As such, the die may be bonded to the support substrate. The bondingphase may last approximately 30 ms. Thereafter, the laser may be turnedoff and the needle may ascend to the ready phase rapidly. Conversely,the laser may be turned off before the needle begins to ascend, or atsome point during the ascent of the needle tip back to the ready phase,the laser may be turned off. After the ascent of the needle tip to theready phase, the height of the needle tip may overshoot and bounce backunder the height of the ready phase somewhat buoyantly. While some ofthe buoyancy may be attributed to the speed at which the needle tipascends to the ready phase, the speed and the buoyancy may beintentional in order to assist in retracting a tip of the needle from asurface of the wafer tape in the case where the needle has pierced thewafer tape and may be stuck therein.

As depicted in FIG. 4, the timing in which the laser is turned off maybe longer than the timing in which the laser is turned on, where aslower speed of the descent may assist in preventing damage to the die,and as mentioned above, the rapid rate of ascent may assist inextracting the needle tip from the wafer tape more effectively.Nevertheless, as previously stated, the timing shown on FIG. 4 isapproximate, particularly with respect to the idle and ready periods.Therefore, the numerical values assigned along the bottom edge of theFIG. 4 are for reference and should not be taken literally, except whenotherwise stated.

Example Support Substrate

FIG. 5 illustrates an example embodiment of a processed supportsubstrate 500. A support substrate 502 may include a first portion of acircuit trace 504A, which may perform as a negative or positive powerterminal when power is applied thereto. A second portion of the circuittrace 504B may extend adjacent to the first portion of the circuit trace504A, and may act as a corresponding positive or negative power terminalwhen power is applied thereto.

As similarly described above with respect to the wafer tape, in order todetermine where to convey the support substrate 502 to perform thetransfer operation, the support substrate 502 may have a bar code (notshown) or other identifier, which is read or otherwise detected. Theidentifier may provide circuit trace data to the apparatus. The supportsubstrate 502 may further include datum points 506. Datum points 506 maybe visual indicators for sensing by the support substrate sensor (forexample, second sensor 246 in FIG. 2) to locate the first and secondportions of the circuit trace 504A, 504B. Once the datum points 506 aresensed, a shape and relative position of the first and second portionsof the circuit trace 504A, 504B with respect to the datum points 506 maybe determined based on preprogrammed information. Using the sensedinformation in connection with the preprogrammed information, thesupport substrate conveyance mechanism may convey the support substrate502 to the proper alignment position for the transfer operation.

Additionally, die 508 are depicted in FIG. 5 as straddling between thefirst and second portions of the circuit trace 504A, 504B. In thismanner, the electrical contact terminals (not shown) of the die 508 maybe bonded to the support substrate 502 during a transfer operation.Accordingly, power may be applied to run between the first and secondportions of the circuit trace 504A, 504B, and thereby powering die 508.For example, the die may be unpackaged LEDs that were directlytransferred from a wafer tape to the circuit trace on the supportsubstrate 502. Thereafter, the support substrate 502 may be processedfor completion of the support substrate 502 and used in a circuit orother final product. Further, other components of a circuit may be addedby the same or other means of transfer to create a complete circuit, andmay include control logic to control LEDs as one or more groups in somestatic or programmable or adaptable fashion.

Simplified Example Direct Transfer System

A simplified example of an embodiment of a direct transfer system 600 isillustrated in FIG. 6. The transfer system 600 may include a personalcomputer (PC) 602 (or server, data input device, user interface, etc.),a data store 604, a wafer tape mechanism 606, a support substratemechanism 608, a transfer mechanism 610, and a fixing mechanism 612.Inasmuch as a more detailed description of the wafer tape mechanism 606,the support substrate mechanism 608, the transfer mechanism 610, and thefixing mechanism 612 has been given heretofore, specific details aboutthese mechanisms is not repeated here. However, a brief description ofhow the wafer tape mechanism 606, the support substrate mechanism 608,the transfer mechanism 610, and the fixing mechanism 612 relate tointeractions between the PC 602 and the data store 604 is describedhereafter.

In an embodiment, the PC 602 communicates with data store 604 to receiveinformation and data useful in the transfer process of directlytransferring die from a wafer tape in wafer tape mechanism 606 using thetransfer mechanism 610 on to a support substrate in the supportsubstrate mechanism 608 whereat the die may be fixed upon the supportsubstrate via actuation of a laser or other energy-emitting devicelocated in the fixing mechanism 612. PC 602 may also serve as areceiver, compiler, organizer, and controller of data being relayed toand from each of the wafer tape mechanism 606, the support substratemechanism 608, the transfer mechanism 610, and the fixing mechanism 612.PC 602 may further receive directed information from a user of thetransfer system 600.

Note that, while FIG. 6 depicts directional movement capability arrowsadjacent to the wafer tape mechanism 606 and the support substratemechanism 608, those arrows merely indicate general directions formobility, however, it is contemplated that both the wafer tape mechanism606 and the support substrate mechanism 608 may also be able to move inother directions including rotation in plane, pitch, roll, and yaw, forexample.

Additional details of the interaction of the components of the transfersystem 600 are described with respect to FIG. 7 below.

Detailed Example Direct Transfer System

A schematic of the communication pathways between the respectiveelements of a transfer system 700 may be described as follows.

The direct transfer system may include a personal computer (PC) 702 (orserver, data input device, user interface, etc.), which may receivecommunication from, and provide communication to a data store 704. ThePC 702 may further communicate with a first cell manager 706(illustrated as “Cell Manager 1”) and a second cell manager 708(illustrated as “Cell Manager 2”). Therefore, the PC 702 may control andsynchronize the instructions between the first cell manager 706 and thesecond cell manager 708.

PC 702 may include processors and memory components with whichinstructions may be executed to perform various functions with respectto the first and second cell managers 706, 708, as well as data store704. In an embodiment, PC 702 may include a project manager 710 and aneedle profile definer 712.

Project manager 710 may receive input from the first and second cellmanagers 706, 708 and data store 704 to organize the direct transferprocess and maintain smooth functioning with respect to orientation andalignment of the support substrate with respect to the wafer tape andthe die thereon.

Needle profile definer 712 may contain data regarding the needle strokeperformance profile, which may be used to instruct the transfermechanism regarding the desired needle stroke performance according tothe specific die on the loaded wafer tape and the pattern of the circuittrace on the support substrate. Additional details of the needle profiledefiner 712 are discussed further herein below.

Turning back to data store 704, data store 704 may include memorycontaining data such as a die map 714, which may be specific to thewafer tape loaded in the wafer tape mechanism. As explained previously,a die map may describe the relative locations of each die on the wafertape and the quality thereof for the purpose of providing apre-organized description of the location of specific die. Further, datastore 704 may also include memory containing circuit CAD files 716.Circuit CAD files 716 may contain data regarding a specific circuittrace pattern on the loaded support substrate.

Project manager 710 may receive the die map 714 and circuit CAD files716 from the data store 704, and may relay the respective information tothe first and second cell managers 706, 708, respectively.

In an embodiment, the first cell manager 706 may use the die map 714from data store 704 via a die manager 718. More specifically, diemanager 718 may compare die map 714 with the information received by asensor manager 720, and based thereon, may provide instructions to amotion manager 722 regarding the location of a particular die. Sensormanager 720 may receive data regarding the actual location of die on thewafer tape from a die detector 724. Sensor manager 720 may also instructthe die detector 724 to look for a particular die in a particularlocation according to die map 714. The die detector 724 may include asensor such as the second sensor 244 in FIGS. 2A and 2B. Based on thereceived data of the actual location (either a confirmation or an updateregarding a shift in position) of the die on the wafer tape, the motionmanager 722 may instruct a first robot 726 (illustrated as “Robot 1”) toconvey the wafer tape to an alignment position with the needle of thetransfer mechanism.

Upon reaching the instructed location, the first robot 726 maycommunicate the completion of its movement to a needle controlboardmanager 728. Additionally, the needle control board manager 728 maydirectly communicate with the PC 702 to coordinate the execution of thetransfer operation. At the time of the execution of the transferoperation, the PC 702 may instruct the needle control board manager 728to activate the needle actuator/needle 730, thereby causing the needleto perform a stroke in accordance with the loaded needle profile in theneedle profile definer 712. The needle controlboard manager 728 may alsoactivate the laser control/laser 732, thereby causing the laser to emita beam toward the support substrate as the needle presses down a die viathe wafer tape to execute the transfer operation. As indicated above,the activation of the laser control/laser 732 may occur prior to,simultaneously, during, or after activation, or even a completeactuation, of the needle stroke.

Accordingly, the first cell manager 706 may pass through a plurality ofstates including: determining where to tell the first robot 726 to go;telling the first robot 726 to go to the determined location; turning onthe needle; activating the fixing device; and resetting.

Prior to execution of the transfer operation, the project manager 710may relay the data of the circuit CAD files 716 to the second cellmanager 708. The second cell manager 708 may include a sensor manager734 and a motion manager 736. Using the circuit CAD files 716, thesensor manager 734 may instruct the substrate alignment sensor 738 tofind the datum points on the support substrate and thereby detect andorient the support substrate according to the location of the circuittrace thereon. The sensor manager 734 may receive confirmation orupdated location information of the circuit trace pattern on the supportsubstrate. The sensor manager 734 may coordinate with the motion manager736 to provide instructions to a second robot 740 (illustrated as “Robot2”) to convey the support substrate to an alignment position (i.e., atransfer fixing position) for execution of the transfer operation. Thus,the circuit CAD files 716 may assist the project manager 710 in aligningthe support substrate with respect to the wafer tape such that the diemay be accurately transferred to the circuit trace thereon.

Accordingly, the second cell manager 708 may pass through a plurality ofstates including: determining where to tell the second robot 740 to go;telling the second robot 740 to go to the determined location; andresetting.

It is understood that additional and alternative communication pathwaysbetween all or fewer than all of the various components of the transfersystem 700 described above are possible.

Example Direct Transfer Method

A method 800 of executing a direct transfer process, in which one ormore die is directly transferred from a wafer tape to a supportsubstrate, is illustrated in FIG. 8. The steps of the method 800described herein may not be in any particular order and as such may beexecuted in any satisfactory order to achieve a desired product state.The method 800 may include a step of loading transfer process data intoa PC and/or a data store 802. The transfer process data may include datasuch as die map data, circuit CAD files data, and needle profile data.

A step of loading a wafer tape into a wafer tape conveyor mechanism 804may also be included in method 800. Loading the wafer tape into thewafer tape conveyor mechanism may include controlling the wafer tapeconveyor mechanism to move to a load position, which is also known as anextract position. The wafer tape may be secured in the wafer tapeconveyor mechanism in the load position. The wafer tape may be loaded sothat the die of the semiconductor are facing downward toward the supportsubstrate conveyor mechanism.

The method 800 may further include a step of preparing the supportsubstrate to load into the support substrate conveyor mechanism 806.Preparing the support substrate may include a step of screen printing acircuit trace on the support substrate according to the pattern of theCAD files being loaded into the PC or data store. Additionally, datumpoints may be printed onto the circuit substrate in order to assist inthe transfer process. The support substrate conveyor mechanism may becontrolled to move to a load position, which is also known as anextraction position, whereat the support substrate may be loaded intothe support substrate conveyor mechanism. The support substrate may beloaded so that the circuit trace faces toward the die on the wafer. Inan embodiment, for example, the support substrate may be delivered andplaced in the load position by a conveyor (not shown) or other automatedmechanism, such as in the style of an assembly line. Alternatively, thesupport substrate may be manually loaded by an operator.

Once the support substrate is properly loaded into the support substrateconveyor mechanism in the wafer tape is properly loaded into the wafertape conveyor mechanism, a program to control the direct transfer of thedie from the wafer tape to the circuit trace of the support substratemay be executed via the PC to commence the direct transfer operation808. The details of the direct transfer operation are described below.

Example Direct Transfer Operation Method

A method 900 of the direct transfer operation of causing die to betransferred directly from the wafer tape (or other substrate holdingdie, also called a “die substrate” for simplified description of FIG. 9)to the support substrate is illustrated in FIG. 9. The steps of themethod 900 described herein may not be in any particular order and assuch may be executed in any satisfactory order to achieve a desiredproduct state.

In order to determine which die to place on the support substrate andwhere to place the die on the support substrate, the PC may receiveinput regarding the identification of the support substrate and theidentification of the die substrate containing the die to be transferred902. This input may be entered manually by a user, or the PC may send arequest to the cell managers in control, respectively, of the supportsubstrate alignment sensor and the die detector. The request mayinstruct the sensor to scan the loaded substrate for an identificationmarker, such as a barcode or QR code; and/or the request may instructthe detector to scan the loaded die substrate for an identificationmarker, such as a barcode or QR code.

Using the support substrate identification input, the PC may query thedata store or other memory to match the respective identificationmarkers of the support substrate and the die substrate and retrieve theassociated data files 904. In particular, the PC may retrieve a circuitCAD file associated with the support substrate that describes thepattern of the circuit trace on the support substrate. The circuit CADfile may further contain data such as the number of, relative positionsof, and respective quality requirement of, the die to be transferred tothe circuit trace. Likewise, the PC may retrieve a die map data fileassociated with the die substrate that provides a map of the relativelocations of the specific die on the die substrate.

In the process of executing a transfer of a die to the supportsubstrate, the PC may determine the initial orientation of the supportsubstrate and the die substrate relative to the transfer mechanism andthe fixing mechanism. Within step 906, the PC may instruct the substratealignment sensor to locate datum points on the support substrate. Asdiscussed above, the datum points may be used as reference markers fordetermining the relative location and orientation of the circuit traceon the support substrate. Further, the PC may instruct the die detectorto locate one or more reference points on the die substrate to determinethe outlay of the die.

Once the initial orientation of the support substrate and die substrateare determined, the PC may instruct the respective support substrate anddie substrate conveyance mechanisms to orient the support substrate anddie substrate, respectively, into a position of alignment with thetransfer mechanism and the fixing mechanism.

The alignment step 908 may include determining the location of theportion of the circuit trace to which a die is to be transferred 910,and where the portion is located relative to the transfer fixingposition 912. The transfer fixing position may be considered to be thepoint of alignment between the transfer mechanism and the fixingmechanism. Based on the data determined in steps 910 and 912, the PC mayinstruct the support substrate conveyance mechanism to convey thesupport substrate so as to align the portion of the circuit trace towhich a die is to be transferred with the transfer fixing position 914.

The alignment step 908 may further include determining which die on thedie substrate will be transferred 916, and where the die is locatedrelative to the transfer fixing position 918. Based on the datadetermined in steps 916 and 918, the PC may instruct the wafer tapeconveyance mechanism to convey the die substrate so as to align the dieto be transferred with the transfer fixing position 920.

Once the die to be transferred from the die substrate and the portion ofthe circuit trace to which a die is to be transferred are aligned withthe transfer mechanism and the fixing mechanism, the needle and thefixing device (e.g., laser) may be actuated 922 to effectuate thetransfer of the die from the die substrate to the support substrate.

After a die is transferred, the PC may determine whether additional dieare to be transferred 924. In the case where another die is to betransferred, the PC may revert to step 908 and realign the product anddie substrates accordingly for a subsequent transfer operation. In thecase where there will not be another die transferred, the transferprocess is ended 926.

Example Direct Transfer Conveyor/Assembly Line System

In an embodiment described with respect to FIG. 10, several of thecomponents of the direct transfer apparatus described above may beimplemented in a conveyor/assembly line system 1000 (hereinafter“conveyor system”). In particular, FIGS. 2A and 2B depict the supportsubstrate 210 being held by the support substrate conveyor frame 214 andtensioned by the support substrate holder frame 216. As an alternativeto securing a support substrate conveyor frame 214 in a confined areavia a system of motors, rails, and gear as indicated with respect toapparatus 200, FIG. 10 illustrates the support substrate conveyor frame214 being conveyed through the conveyor system 1000 in which the supportsubstrate goes through an assembly line style process. As the actualmeans of conveyance between operations being performed on the supportsubstrate being conveyed, the conveyor system 1000 may include a seriesof tracks, rollers, and belts 1002 and/or other handling devices tosequentially convey a plurality of support substrate conveyor frames214, each holding a support substrate.

In an embodiment, operation stations of the conveyor system 1000 mayinclude one or more printing stations 1004. As blank support substratesare conveyed to the printing station(s) 1004, a circuit trace may beprinted thereon. In the case that there are multiple printing stations1004, the multiple printing stations 1004 may be arranged serially, andmay be configured to perform one or more printing operations each so asto form a complete circuit trace.

Additionally, in the conveyor system 1000, the support substrateconveyor frame 214 may be conveyed to one or more die transfer stations1006. In the event that there are multiple die transfer stations 1006,the multiple die transfer stations 1006 may be arranged serially, andmay be configured to perform one or more die transfers each. At thetransfer station(s), the support substrates may have one or more dietransferred and affixed thereto via a transfer operation using one ormore of the direct transfer apparatus embodiments described herein. Forexample, each transfer station 1006 may include a wafer tape conveyancemechanism, a transfer mechanism, and a fixing mechanism. In anembodiment, a circuit trace may have been previously prepared on thesupport substrate, and as such, the support substrate may be conveyeddirectly to the one or more transfer stations 1006.

In the transfer stations 1006, the wafer tape conveyance mechanism, thetransfer mechanism, and the fixing mechanism may be aligned with respectto the conveyed support substrate conveyor frame 214 upon entering thestation. In this situation, the transfer station 1006 components mayrepeatedly perform the same transfer operation in the same relativeposition on each support substrate as the plurality of supportsubstrates are conveyed through the conveyor system 1000.

Moreover, the conveyor system 1000 may further include one or morefinishing stations 1008 to which the support substrate may be conveyedto have final processing performed. The type, amount, and duration ofthe final processing may depend on the features of the product and theproperties of the materials used to make the product. For example, thesupport substrate may receive additional curing time, a protectivecoating, additional components, etc., at the finishing station(s) 1008.

Second Example Embodiment of a Direct Transfer Apparatus

In another embodiment of a direct transfer apparatus, as seen in FIGS.11A and 11B, a “light string” may be formed. While many of the featuresof apparatus 1100 may remain substantially similar to those of apparatus200 of FIGS. 2A and 2B, support substrate conveyance mechanism 1102, asdepicted in FIGS. 11A and 11B, may be configured to convey a supportsubstrate 1104 that is different than the support substrate 210.Specifically, in FIGS. 2A and 2B, the support substrate conveyancemechanism 202 includes the support substrate conveyor frame 214 and thetensioner frame 216, which secure the sheet-like support substrate 218under tension. In the embodiment of FIGS. 11A and 11B, however, thesupport substrate conveyance mechanism 1102 may include a supportsubstrate reel system.

The support substrate reel system may include one or two circuit tracereels 1106 that are wound with a “string circuit,” which may include apair of adjacently wound conductive strings or wires as the supportsubstrate 1104. In an instance with only one reel, the reel 1106 may belocated on a first side of the transfer position, and the pair ofconductive strings (1104) may be wound around the single reel 1106.Alternatively, there may be two circuit trace reels 1106 located on thefirst side of the transfer position, where each reel 1106 contains asingle strand of the string circuit and the strands are then broughttogether to pass through the transfer position.

Regardless of whether one reel 1106 or two reels 1106 are implemented,the die transfer process of forming the string circuit may besubstantially similar in each case. In particular, the conductivestrings of the support substrate 1104 may be threaded from the reel(s)1106 across the transfer position and may be fed into a finishing device1108. In an embodiment, the finishing device 1108 may be: a coatingdevice to receive a protective coating, for example, of a translucent ortransparent plastic; or a curing apparatus, which may finish curing thestring circuit as a part of final processing of the product.Additionally, or alternatively, the circuit string may be fed ontoanother reel, which may wind up the string circuit thereon before finalprocessing of the string circuit. As the conductive strings of thesupport substrate 1104 are pulled through the transfer position, thetransfer mechanism 206 may be actuated to perform a needle stroke (asdescribed above) to transfer die 220 to the conductive strings of thesupport substrate 1104 so that electrical contact terminals of the die220 are placed, respectively, on the adjacent strings, and the fixingmechanism 208 may be actuated to affix the die 220 in position.

Furthermore, apparatus 1100 may include tensioning rollers 1110 on whichthe conductive strings of the support substrate 1104 may be supportedand further tensioned against. Thus, the tensioning rollers 1110 mayassist in maintaining tension in the formed string circuit so as toenhance the die transfer accuracy.

In FIG. 11B, die 220 are depicted as having been transferred to theconductive strings of the support substrate 1104, thereby uniting (tosome extent) the conductive strings of the support substrate 1104 andforming a string circuit.

Third Example Embodiment of a Direct Transfer Apparatus

In an additional embodiment of a direct transfer apparatus, as seen inFIG. 12, apparatus 1200 may include a wafer tape conveyance mechanism1202. In particular, in lieu of the wafer tape conveyor frame 222 andthe wafer tape holder frame 224 shown in FIGS. 2A and 2B, the wafer tapeconveyance mechanism 1202 may include a system of one or more reels 1204to convey die 220 through the transfer position of the apparatus 1200 totransfer die to a single substrate. In particular, each reel 1204 mayinclude a die substrate 1206 formed as a narrow, continuous, elongatedstrip having die 220 attached consecutively along the length of thestrip.

In the case where a single reel 1204 is used, a transfer operation mayinclude conveying the support substrate 210 via the support substrateconveyance mechanism 202 substantially as described above, using motors,tracks, and gears. However, the wafer tape conveyance mechanism 1202 mayinclude a substantially static mechanism, in that, while the die 220 maybe fed continuously through the transfer position by unrolling the diesubstrate 1206 from reel 1204, the reel 1204 itself main remain in afixed position. In an embodiment, the tension of the die substrate 1206may be maintained for stability purposes by tensioning rollers 1208,and/or a tensioning reel 1210, which may be disposed on a side of theapparatus 1200 opposite the reel 1204. The tensioning reel 1210 may rollup the die substrate 1206 after the die have been transferred.Alternatively, the tension may be maintained by any other suitable meansto secure the die substrate 1206 so as to assist in pulling it throughthe transfer position after each transfer operation to cycle through thedie 220.

In an embodiment where multiple reels 1204 are used, each reel 1204 maybe disposed laterally adjacent to other reels 1204. Each reel 1204 maybe paired with a specific transfer mechanism 206 and a specific fixingmechanism 208. In this case, each respective set of transfer mechanismsand fixing mechanisms may be arranged with respect to the supportsubstrate 210 such that multiple die may be placed in multiple locationson the same support substrate 210 simultaneously. For example, in anembodiment, the respective transfer positions (i.e., the alignmentbetween a transfer mechanism and a corresponding fixing mechanism) maybe in a line, offset, or staggered so as to accommodate various circuittrace patterns.

Regardless of whether one reel 1204 or a plurality of reels 1204 areimplemented, the die transfer operation may be relatively similar to thetransfer operation as described above with respect to the first exampleembodiment of the apparatus 200. For instance, the support substrate 210may be conveyed to a transfer position (die fixing position) in the samemanner as described above via the support substrate conveyance mechanism202, the transfer mechanism(s) 206 may perform a needle stroke totransfer the die 220 from the die substrate 1206 to the supportsubstrate 210, and the fixing mechanism 208 may be actuated to assist inaffixing the die 220 to the support substrate 210.

Note that in an embodiment with a plurality of reels 1204, a circuittrace pattern may be such that not every transfer mechanism may need tobe actuated simultaneously. Accordingly, multiple transfer mechanismsmay be actuated intermittently as the support substrate is conveyed tovarious positions for transfer.

Fourth Example Embodiment of a Direct Transfer Apparatus

FIG. 13 depicts an embodiment of a direct transfer apparatus 1300. As inFIGS. 2A and 2B, the support substrate conveyance mechanism 202 may bedisposed adjacent to the wafer tape conveyance mechanism 204. However,there is a space between the conveyance mechanisms 202, 204 in which atransfer mechanism 1302 may be disposed to effectuate the transfer ofthe die 220 from the wafer tape 218 to the support substrate 210.

The transfer mechanism 1302 may include a collet 1304 that picks the die220, one or more at a time, from the wafer tape 218 and rotates about anaxis A that extends through arm 1306. For example, FIG. 13 depicts thewafer tape 218 facing the support substrate 210 such that the collet1304 may pivot 180 degrees about pivot point 1308 (see directional pivotarrows) between the die-carrying surface of the wafer tape 218 and thetransfer surface of the support substrate 210. That is, the direction ofextension of the collet 1304 pivots in a plane that is orthogonal to thesurface or plane of transfer of both the wafer tape 218 and the supportsubstrate 210. Alternatively, in some embodiments, the arm structure ofthe collet may be arranged to pivot between two parallel surfaces, andthe arm of the collet may pivot along parallel plane. Thus, when facingthe wafer tape 218, the collet 1304 may pick the die 220 and thenimmediately pivot to the surface of the support substrate 210 to be inline with the fixing mechanism 208. The collet 1304 then releases thedie 220 so as to transfer the die 220 to be affixed to the circuit trace212 on the support substrate 210.

In an embodiment, the transfer mechanism 1302 may include two or morecollets (not shown) extending from the arm in different directions. Insuch an embodiment, the collets may be indexed rotatingly 360 degreesthrough the collet stop locations and picking and transferring a dieevery time a collet passes the wafer tape 218.

Additionally, the one or more collets 1304 may pick and release the die220 from the wafer tape using positive and negative vacuum pressurethrough the collet 1304.

First Example Embodiment of a Direct Transfer Apparatus Having aMicro-Adjustment Assembly

Illustrated in FIG. 14 is an embodiment of a direct transfer apparatus1400. In the embodiment depicted, a micro-adjustment mechanism 1402 isattached to a wafer tape conveyance mechanism 1404, which may assist inthe direct transfer of semiconductor device die 220 from a wafer tape218 to a support substrate 210. While many features of the transferapparatus 1400 may remain substantially similar to those of apparatus200 in FIGS. 2A and 2B, some distinctions are discussed herein belowwith respect to FIGS. 14-18 including the implementation of themicro-adjustment mechanism 1402 that makes micro adjustments (e.g., 5microns to 50 microns, or 1 micron to 1000 microns, or 0.5 micron to5000 microns, etc.) to the orientation and/or position of wafer tape 218and die 220 during the die transfer process.

As an overview, the transfer apparatus 1400 may include the supportsubstrate conveyance mechanism 202 (also depicted with respect to FIGS.2A and 2B), and wafer tape conveyance mechanism 1404. The wafer tapeconveyance mechanism 1404 is, in general, functionally similar to thewafer tape conveyance mechanism 204, as it includes a wafer tapeconveyor frame 1406 and a wafer tape holder frame 1408. In general,support substrate conveyance mechanism 202 and the wafer tape conveyancemechanism 1404 may be discussed herein as mechanisms that provide“coarse movement,” as they are generally moved for larger movements(relative to micro movements) between successive die transfer locations.However, as indicated above, the wafer tape conveyance mechanism 1404 inthe embodiment of FIG. 14 includes micro-adjustment mechanism 1402,discussed in detail below. While the mechanisms that provide coarsemovements may still be used to adjust between transfer locations on asmaller scale as needed, including a micro distance, it is consideredthat the coarse movement mechanisms are better suited for larger, macromovements (e.g., ˜1-2 mm or greater). Thus, the implementation of amicro-adjustment mechanism in connection with a coarse movementconveyance mechanism may be advantageous for several situations. Forexample, a micro adjustment may be made in addition to a coarse movementwhen the coarse movement conveyance mechanism has overshot a transferlocation, undershot a transfer location, or is shuddering near atransfer location due to stopping from a coarse movement, such that atransfer alignment is slightly off, e.g., on a micro scale.

The micro-adjustment mechanism 1402, in conjunction with cell manager706 (FIG. 7), may perform real-time micro-adjustments that align and/ormore closely align the support substrate 210 and the die 220 during thedie transfer process. In an embodiment, the transfer apparatus 1400 mayperform micro-adjustments for different purposes, including compensatingfor vibrational movement after stopping a moving component, and/or forthe purpose of speeding overall die transfer operations in which themotion speed of conveyance mechanisms 202, 1404 is slowed before asubsequent die transfer (instead of a full stop at each transferoperation).

For example, in one aspect, the micro-adjustment mechanism 1402 correctspositional errors caused by vibration from starting and/or stoppingconveyance of the wafer tape conveyor frame 1406. The die transfer ratemay range from about 6-450 die or more placed per second. In general, asthe transfer rate increases, the mechanical complexity and weight of theconveyance apparatus may increase as well. The increases in the speed ofmoving masses and the increases in transfer rate may collectively addsystem component vibrations when those masses accelerate quickly andthen come to an abrupt stop. The settling time required to dissipate thevibrations may create time-related inefficiencies in die transfer. In anembodiment, micro-adjustment of the wafer tape holder frame 1408 mayincrease system efficiency by counteracting vibrations, which affect therelative position of the die, to reduce or eliminate settling time ofthe wafer tape conveyance mechanism 1404.

In an embodiment, micro-adjustments may be made to increase systemefficiency by allowing the wafer tape conveyance mechanism 1404 toremain continually in motion and transfer the die 220 to the supportsubstrate 210 while the wafer tape holder frame 1408 is still in motion,without repeated starts and stops as the wafer tape conveyance mechanism1404 travels from one transfer location to the next transfer location.

Considering the structure of the apparatus, FIG. 15A depicts anisometric view of a micro-adjustment mechanism 1500 (hereafter“microadjust mechanism 1500”), according to one embodiment. Themicroadjust mechanism 1500 may include an actuator 1502, an actuatorflange 1504 having a support arm 1504A against which the actuator 1502may be secured, a wafer support block 1506 on which to secure wafer tapeholder frame 1408 for holding wafer tape 218, and one or more springmembers 1508 connecting the wafer support block 1506 to the actuatorflange 1504. In an embodiment not shown, the actuator flange 1504 may bein direct or indirect connection with the wafer tape holder frame 1408.The microadjust mechanism 1500 may be securely fastened to the wafertape conveyor frame 1406 (as depicted in FIG. 14) such that themicroadjust mechanism 1500 moves with the wafer tape conveyor frame 1406and makes small independent adjustments to the position of the wafertape 218.

According to one embodiment, the actuator 1502 may include an elongatedrod that may be mounted on the actuator flange 1504 with an actuatorbracket assembly 1510. The actuator bracket assembly 1510 may includeone or more fastening means such as, for example, a socket head capscrew, latch, clip, weld, etc. The microadjust mechanism 1500 mayinclude a plurality of through holes 1512 located in the actuator flange1504 for attaching the microadjust mechanism 1500 to the wafer tapeconveyor frame 1406 with an appropriate fastener (not shown).

The actuator 1502 is disposed on the actuator flange 1504 such that,when assembled, the body of the actuator 1502 is slidable in a singledirection with respect to a surface along the actuator flange 1504.However, the actuator 1502 remains in a fixed orientation with respectto the distance from and direction of extension along the actuatorflange 1504. It should be appreciated that, although depicted as acylindrical body bolted to the actuator flange 1504 with socket head capscrews via the actuator bracket assembly 1510, the actuator 1502 maytake many shapes other than the cylindrical form shown in FIG. 15A, andmay be fastened to the actuator flange 1504 in any way such that theactuator flange 1504 and the actuator 1502 operate as a single unit withrespect to one another.

The actuator 1502 may be a piezoelectric actuator. Piezoelectricactuators (also called piezoelectric transducers, translators, etc.)convert electrical energy into linear motion. Alternatively, theactuator 1502 may include a motion control actuator, other than apiezoelectric actuator, that may be configures to make fast and precisemovements. Example alternative actuators include linear motors, servo orstepper motors with a ball screw, a voice coil, etc. Using apiezoelectric actuator for example, the actuator 1502 may apply arelatively large pushing force (e.g., 1000+N) at a first end of actuator1502 in contact with wafer support block 1506, when a signal stimulationis applied via an electrical connector 1514 disposed at a second end ofactuator 1502.

The actuator 1502 may connect to one or more system controllers via theelectrical connector 1514. As previously discussed with respect to FIG.7, several system control mechanisms may be configured to control theactuator 1502. The system controllers may control operational aspects ofthe actuator 1502, including a stroke distance of the first end of theactuator 1502 based on the signal stimulation. An exemplary controllersystem may be, for example, the sensor manager 720, the motion manager722, the sensor manger 734, and/or the motion manager 736, as shown withrespect to FIG. 7.

It should be appreciated by those skilled in the art ofelectromechanical control systems that actuator responses are routinelycontrollable via a single channel or multi-channel controller system inconjunction with one or more signal amplifiers. According to anembodiment, the actuator 1502 is controllable such that the first end ofthe actuator 1502 moves the position of the wafer tape holder frame 1408and, thus, the wafer tape 218, when actuated. The wafer tape holderframe 1408 may be movable with respect to the actuator flange 1504 viathe one or more spring members 1508 (in an embodiment having springmembers). Alternatively, with other motion control actuators that canoutput force in more than one direction, the wafer tape holder frame1408 may be movable without a spring member because the actuator itselfis capable of causing motion in the return direction. Also, the actuator1502 may be disposed in the structure of the system in a differentposition that is depicted. That is, it is contemplated that the positionof the actuator 1502, relative to the coarse movement conveyancemechanism and the substrate or transfer mechanism that is beingmicroadjusted, may be different. For example, the actuator 1502 may bein-plane with the microadjusted member (i.e., whichever component hasthe position thereof being adjusted, either the coarse conveyancemechanisms or the transfer mechanisms, or a combination thereof),stacked between the coarse movement conveyance mechanism and themicroadjusted member, etc. Once the wafer tape holder frame 1408, wafertape 218, and die 220 are collectively displaced to the intendedlocation (i.e., an alignment position is attained), the transfermechanism 206 (FIG. 14) may transfer the die 220 to the supportsubstrate 210 with precise timing and location accuracy. An alignmentposition is precise when the die is positioned at the predetermined andintended location, where the actual location is within a predeterminedrange of error (i.e., the location is accurate within a predeterminedtolerance). An example of a predetermined range of tolerance may be, forexample, between 10-50 microns. Other tolerances are contemplated.

As indicated above, in an embodiment, the spring members 1508 connectthe wafer support block 1506 and the actuator flange 1504 such that thefirst end of the actuator 1502 may apply an actuation force (illustratedas an arrow 1502A indicating the direction of the force). Actuationforce 1502A displaces the wafer support block 1506, which translates todisplacement of wafer tape holder frame 1408 from a first (resting)position, to a second position along the axis of actuation (depicted inFIG. 15A as the X-axis). The displacement is a predetermined distancefrom the first position with respect to the actuator flange 1504. Thespring members 1508 may deform slightly to allow the displacement of thewafer tape holder frame 1408 by moving the wafer support block 1506along the axis of the actuation force 1502A. By way of example, adisplacement of the wafer tape, as used herein, may range from about 5microns to about 200 microns. After application of the actuation force1502A, a return force (illustrated as an arrow 1508A indicating thedirection of the force) may be applied by the restoring force of thespring members 1508 such that the first end of the actuator 1502, if notalready returned to the at rest position by other means, is forced backinto the at rest position relative to the actuator flange 1504. Thus,the spring members may serve as return members.

The actuator flange 1504 (and particularly, the spring members 1508) maybe constructed from suitable materials having satisfactory elasticmechanical properties, which may depend on the particular spring design.For example, in the illustrated embodiment, materials such as alloysteel, carbon steel, cobalt-nickel, a copper-based alloy, a nickel-basedalloy, a titanium alloy, aluminum, etc. may be satisfactory.Additionally, and/or alternatively, plastics and other compositionmaterials are contemplated. It should be appreciated the geometry of themicroadjust mechanism 1500 and the construction material thereof mayvary and are not be limited to those described herein.

According to one embodiment, the actuator flange 1504 and spring members1508 (or portions thereof) may be unified in that they are manufacturedfrom a single piece of material. In other aspects, they may bemanufactured as separate components and fastened together (e.g., viawelding or other fastening techniques) to form a unified (single-piece)microadjust mechanism 1500. For example, when manufactured from a singlepiece of stock, the plurality of spring members 1508 may be formed byremoving (e.g., via machining, electro discharge machining (EDM), etc.)a portion of the actuator flange 1504 (where portions removed are shownas swirl-shaped cavities in FIG. 15A). Although depicted in FIGS. 15A-17as arched spring arms, the spring members 1508 may be another form orshape suitable, such as coil springs, for returning the wafer tapeholder frame 1408 to the first (resting) position after the actuationforce 1502A is removed.

One of the possible benefits of a piezoelectric actuator is the variablycontrollable actuation and available pushing force of the actuator 1502.The strength of actuation coupled with the speed and precision ofactuation may provide precision in locating adjustments that that mayposition die to be transferred. Another benefit is that the speed andprecision of actuation provide micro-adjustments that counteractvibrations. For example, with respect to counteracting vibrationalforces, the microadjust mechanism 1500 may be configured as shown with asingle actuator 1502 to assist the system to counteract vibration causedby a quick acceleration of the masses associated with the supportsubstrate conveyor frame 214 followed by an abrupt deceleration (i.e.,stop), regardless of the direction of travel preceding the stop. Statedin another way, when actuating the actuator to counteract a vibrationcaused by a quick stop of the wafer tape conveyance mechanism 1404 onwhich the microadjust mechanism 1500 is connected, the direction oftravel of the microadjust mechanism 1500 and wafer tape conveyancemechanism 1404 prior to the stop may not matter when considering thedirection of actuation of the actuator 1502. At least some of anyresultant vibrations caused by the stop may be counteracted with asingle actuator.

Piezoelectric actuators may provide micro-adjustments by pushing (e.g.,by applying linear force in one direction), but may not have equalpulling ability (e.g., applying linear force in the opposite direction).For example, a single-direction actuation may have physical limitationswhen being used for precise actuation (e.g., positional adjustment) in asituation in which in a system having movement capabilities in twodirections (e.g., positive direction along the X axis and negativedirection along the X axis). Accordingly, when using a piezoelectricactuator for the actuator 1502, it may be advantageous to provide amicroadjust mechanism configured to actuate in more than one direction(discussed further herein with respect to FIGS. 16 and 17).

FIG. 15B illustrates a schematic cross-sectional view, takenapproximately along line XVB-XVB shown in FIG. 15A, of the wafer tapeconveyance mechanism 1404, including the micro-adjustment mechanism1500, according to an embodiment of the present application. The needle226 and needle retraction support 230 are shown for orientation of thewafer tape conveyor mechanism 1404. To be clear, FIG. 15A depicts themicro-adjustment assembly 1500 in an orientation upside down from thatdepicted in FIG. 15B. As depicted in FIG. 15B, wafer tape holder frame1408 is configured to secure the wafer tape 218, and themicro-adjustment assembly 1500 may make micro adjustments to theposition of the wafer tape 218. The wafer tape conveyor frame 1406 ismechanically coupled with the actuator flange 1504. Additionally, FIG.15B depicts gaps 1516 in the actuator flange 1504. The gaps 1516represent the cavity spaces from which portions of material was removed(i.e., as discussed above in an embodiment in which the actuator flange1504 and wafer support block 1506 are created from a single stock piece)to form the spring members 1508. In general, gaps 1516 represent themaximum amount of space in which the micro adjustments to the positionof the die 220 may be made. In an alternative embodiment (not shown), anactuator flange and a wafer support block may be two separate componentsthat have been mechanically coupled by fasteners and springs other thanthose depicted and explicitly described herein, in which case, the gaps1516 may still represent the space in which positional adjustment may bemade between the alternatively coupled actuator flange and wafer supportblock.

FIG. 15C illustrates another section view, taken approximately alongline XVC-XVC shown in FIG. 15A, of the micro-adjustment assembly 1500,according to an embodiment. The needle and the retraction support areomitted in this view for clarity. Note, though the wafer tape conveyorframe 1406 is depicted as spaced slightly from actuator flange 1504 inorder to clearly depict the distinction in components, it is understoodby those skilled in the art that, in use, the wafer tape conveyor frame1406 is mechanically coupled with the wafer tape holder frame 1408 viaattachment to the actuator flange 1504. As depicted in FIG. 15C, theactuator 1502 may be mounted on or held in close proximity to theactuator flange 1504 with an actuator bracket assembly 1510, which mayinclude bushings, gaskets, washers, brackets, etc. In an embodiment,maintaining an offset between actuator 1502 and actuator flange 1504 mayminimize friction during movement, for example.

Second Example Embodiment of a Direct Transfer Apparatus Having aMicro-Adjustment Assembly

FIG. 16 illustrates a bottom view of a micro-adjustment mechanism 1600(hereafter “microadjust mechanism 1600”) having a first actuator 1602and a second actuator 1604 for performing micro-adjustments of one ormore components of the apparatus, according to another embodiment of thepresent application. While many features of microadjust mechanism 1600may remain substantially similar to those of the microadjust mechanism1500 in FIG. 15A, some distinctions are discussed herein below withrespect to the second actuator 1604.

The microadjust mechanism 1600 includes the first actuator 1602 having adistal end positioned to contact a first side of a wafer support block1606, which is configured to secure wafer tape holding frame for holdinga wafer tape (not shown in FIG. 16). In addition, the microadjustmechanism 1600 includes a second actuator 1604 having a distal end inpositioned to contact the wafer support block 1606 at a position 180degrees opposite the distal end of the first actuator 1602. Theproximity of the respective distal ends of the first actuator 1602 andsecond actuator 1604 to the wafer support block 1606 may include directcontact, indirect contact, abutment, adjacent, etc. The microadjustmechanism 1600 may include an actuator flange 1608 to which the supportblock 1606 is secured. Moreover, the actuator flange 1608 may includesupport arms 1608A and 1608B against which the first actuator 1602 andsecond actuator 1604 are secured. In an embodiment that may furtherimplement a spring-based return system, such as is depicted in FIG. 16,the microadjust mechanism 1600 may also include a plurality ofdeformable spring members 1610 connecting the wafer support block 1606to the actuator flange 1608. The microadjust mechanism 1600 may besecurely fastened to the wafer tape conveyor frame 1406 via holes 1612(in a similar manner as microadjust mechanism 1500 as depicted in FIG.15B) such that the microadjust mechanism 1600 may move with the wafertape conveyor frame (when attached thereto) and make micro adjustmentsto the position of the wafer tape.

Accordingly, the spring members 1610 connect the wafer support block1606 and the actuator flange 1608 such that the distal end of the firstactuator 1602 may apply an actuation force 1602A that displaces thewafer support block 1606 from a first (resting) position, to a secondposition along the axis of actuation (depicted in FIG. 16 as theX-axis). The displacement may be a variable, predetermined distance fromthe first position with respect to the actuator flange 1608. The springmembers 1610 may temporarily deform slightly to allow the displacementof the wafer support block 1606 by moving the wafer support block 1606along the axis of the actuation force 1602A. After application of theactuation force 1602A, the spring members 1610 may apply a return springforce 1610A such that the distal end of the first actuator 1602, if notalready returned to the first position, is forced back into the firstposition relative to the actuator flange 1608.

Additionally, and/or alternatively, the second actuator 1604 may applyan actuation force 1604A to assist in returning the wafer support block1606 to the first position. In the event that the embodiment includes aspring-based return system, the return spring force 1610A may act on thewafer support block 1606 to return the wafer support block 1606 to thefirst position. Moreover, the actuation force 1604A may be greater thana return spring force 1610B, and may provide additional control withrespect to velocity of conveyance, acceleration of the conveyancerelative to the actuator flange 1608, and other controllable factorsthat dictate a precise return of the wafer support block 1606 to thefirst position relative to the actuator flange 1608. The return force1610B may also return the wafer support block 1606 to the first positionwhen the second actuator 1604 is performing the micro-adjustmentoperation as described above. That is to say, the first position is thecommon resting position, and a third position may be reached when thesecond actuator 1604 pushes the wafer support block 1606 toward thefirst actuator 1602.

According to an embodiment, the precise actuation control formicro-adjustment of the wafer support block 1606, in two directionsalong a single axis, may provide greater optimization capabilities tothe micro-adjustment movements when transferring die. Each of the firstactuator 1602 and the second actuator 1604, respectively, may beconnected to a control system (not shown) via a corresponding one ofconnectors 1614 and 1616, respectively. Thus, the embodiment such asthat described with respect to FIG. 16 provides for alignment timing intwo directions of travel along a single axis.

Third Example Embodiment of a Direct Transfer Apparatus Having aMicro-Adjustment Assembly

Additionally, and/or alternatively, FIG. 17 illustrates a bottom view ofan embodiment of a micro-adjustment mechanism 1700 having four microactuators: first actuator 1702, second actuator 1704, third actuator1706, and fourth actuator 1708. Many features of microadjust mechanism1700 may remain substantially similar to those of the microadjustmechanisms 1500 and 1600, respectively in FIGS. 15 and 16. For example,first actuator 1702 and second actuator 1704 may be disposed againstactuator flange 1710 on support arms 1710A and 1710B, respectively, inthe micro-adjustment mechanism 1700 as described with respect to firstactuator 1602 and second actuator 1604. However, actuator flange 1710may have additional support arms 1710C and 1710D, on which may besupported, respectively, a third actuator 1706 and a fourth actuator1708. As depicted, it is contemplated that the third actuator 1706 andthe fourth actuator 1708 may be aligned collinearly opposite each other,positioned to contact the wafer support block 1712 at locations rotated90 degrees from the first actuator 1702 and the second actuator 1704,respectively. That is, the third actuator 1706 and the fourth actuator1708 may be oriented perpendicularly with respect to the collinearalignment of the first actuator 1702 and the second actuator 1704 toadjust the position of the die in a direction perpendicular to the lineof direction in which the first actuator 1702 and the second actuator1704 are able to make adjustments. Note, opposite facing actuators mayserve as return members to reset the adjusted feature in a neutralstate.

First Illustrative Example of a Method for Performing Direct TransfersUsing a Direct Transfer Apparatus Having a Micro-Adjustment Assembly

In an embodiment, as the frame holding the wafer tape is conveyed fromlocation to location, the conveyance mechanism holding the wafer framemay move to the transfer location, and after coming to an abrupt stop oreven slowing significantly, a micro-adjustment that fine-tunes thetransfer location and/or removes system vibrations may be performed.Once adjusted, the system then transfers the die. FIG. 18 depicts amethod 1800 of a direct transfer operation of an embodiment of a directtransfer apparatus with a micro-adjustment mechanism, in which theconveyance mechanisms may either stop at each transfer alignment or maynot stop completely at each transfer alignment, but rather may merelyslow down.

The steps of the method 1800 described herein may not be in anyparticular order and, as such, may be executed in any satisfactory orderto achieve a desired product state. For ease of explanation, the method1800 is described as being performed at least in part by a directtransfer apparatus with a micro-adjustment mechanism such as, forexample, those depicted in FIGS. 14-17. Note, for the sake ofconvenience, the steps of method 1800 are described as if themicro-adjustment mechanism is disposed with the wafer substrateconveyance mechanism. However, it is contemplated that the principle ofa micro-adjustment mechanism may be adapted to be implemented on othercoarse movement mechanisms as indicated above. Therefore, it is alsocontemplated that the steps of method 1800 may also be applicable asadapted for an apparatus in which the micro-adjustment mechanism isdisposed on a coarse movement mechanism other than as shown in FIGS.14-17.

The example method 1800 of direct transfer operation (as well as eachprocess described herein) is illustrated as a logical flow graph, whereeach respective operation may represent a sequence of operations thatmay be implemented by hardware, software, a combination thereof. In somesituations, one or more of the operations may be implemented by one ormore human users.

In the context of software, the operations may representcomputer-executable instructions stored on one or more computer-readablemedia that, when executed by one or more processors, perform the recitedoperations. Generally, computer-executable instructions may includeroutines, programs, objects, components, data structures, and the likethat perform particular functions or implement particular abstract datatypes.

The computer-readable media may include non-transitory computer readablestorage media, which may include hard drives, floppy diskettes, opticaldisks, CD-ROMs, DVDs, read-only memories (ROMs), random access memories(RAMs), EPROMS, EEPROMS, flash memory, magnetic or optical cards,solid-state memory devices, or other types of storage media suitable forstoring electronic instructions. In addition, in an embodiment, thecomputer-readable media may include a transitory computer-readablesignal (in compressed or uncompressed form). Examples ofcomputer-readable signals, whether modulated using a carrier or not,include, but are not limited to, signals that a computer system hostingor running a computer program may be configured to access, includingsignals downloaded through the Internet or other networks. Finally,unless otherwise noted, the order in which the operations are describedis not intended to be construed as a limitation, and any number of thedescribed operations may be combined in any order and/or in parallel toimplement the process.

Now considering FIG. 18 in greater detail, at 1802, the PC (describedherein above with respect to FIG. 7) may instruct the system to align afirst substrate (e.g., a die carrying substrate such as a wafer tape onwhich die are secured), a second substrate (a transfer substrate towhich the die are to be transferred such as a circuit board or otherdie, etc.), and a transfer mechanism into the alignment position(discussed further herein). That is, in an embodiment, the PC mayinstruct any one or all of a first substrate conveyance mechanism, asecond substrate conveyance mechanism, or the transfer mechanism to moveinto a transfer alignment position, in which a die is to be transferredfrom the first substrate to a transfer location on the second substrate.Note, it is contemplated that at least one of the first substrateconveyance mechanism, the second substrate conveyance mechanism, or thetransfer mechanism has implemented therewith a micro-adjustmentmechanism to minimize misalignment that may result from coarse movementand/or other factors in the transfer process.

As used herein, an alignment position may be a position within a rangeof alignment distances between the moving components. For example, analignment position may occur when all three components (e.g., thetransfer mechanism, the first substrate carrying the die to betransferred, and the second substrate having the target transferlocation for the die) are aligned such that any variance in alignment(i.e., misalignment) between the three components ranges from 10 micronsto 75 microns. In an embodiment, an alignment position may include asmaller range of allowable misalignment such as 10 microns to 20microns. Other misalignment tolerance ranges are contemplated, and thus,are not limited to ranges discussed explicitly herein.

With further respect to step 1802 above, in an embodiment, the systemmay align the substrates with the transfer mechanism to prepare for adie transfer using a full stop of the coarse movement(s) from the systemcomponent once the alignment position is attained. Upon stopping, avibration of the structure may occur. For example, vibration may cause ashift in alignment as large as 30 microns to 50 microns as a result ofthe deceleration of moving masses.

Additionally, and/or alternatively, in an embodiment, the system mayalign the substrates with the transfer mechanism to prepare for a dietransfer while one or more of the three components are in motion. Forexample, a conveyance mechanism conveying the first substrate may haveinstructions to maintain a deliberate, slow, continuous movement; ormovement may be faster between coarse movements and then the system mayreduce the velocity of the moving component as it approaches the desiredtransfer location. Thus, at a precise, determinable moment in time, thesystem may adjust the micro-adjustment mechanism in the axis of travel,for example, at 180 degrees from the direction of travel of thecomponent in coarse movement at a speed such that the position of thedie being transferred is motionless with respect to the target positionon the support. That is, the relative velocity of the component beingmicro-adjusted becomes zero. At the instant that the die is most closelyaligned with the target transfer position, the transfer mechanism isactuated to transfer the die off of the first substrate. A possibleadvantage of the embodiment implementing continuous movement may includemanufacturing efficiencies gained from time saved compared to waitingfor system vibrations to settle at each transfer location.

In either embodiment, to determine the timing of the actuation anddetermine the control parameters at which the actuator is to beactuated, the cell manager (discussed with respect to FIG. 7) maydetermine real-time operational factors including velocity,acceleration, position, alignment between moving components, time, andother factors. Accordingly, prior to each actuation the sensor manager,motion manager, and die manager determine the timing and rate ofactuation for operating the actuator.

At 1804, the transfer apparatus makes one or more micro-adjustments tothe position of one or more of the components, as needed, to improve thealignment position. The one or more micro-adjustments may be executed bydisplacing a component via actuation of at least one micro-adjustmentactuator, thereby addressing any micro-sized misalignment. Adisplacement may include, for example, displacing the first substrate,with the micro-adjustment actuator, from a first position relative tothe actuator flange to a second position relative to the actuatorflange. The displacement may be variably controlled, and as such, may bea predetermined distance that aligns the die to be transferred from thefirst substrate to the transfer location on the second substrate withgreater precision to ensure a valid placement. That is to say, thealignment position described with respect to 1802 may be improved inreal-time during the transfer process by reducing and/or eliminating anydie misalignment, despite the micro scale of action occurring due tovibrational movement or continuous movement.

At 1806, the apparatus transfers the semiconductor device die from thefirst substrate to the second substrate via actuation of the transfermechanism (e.g., cycling a needle/pin/wire, pivoting collet, etc.).

At step 1808, the component(s) to which a micro-adjustment was made maybe returned to the neutral position (at rest). For example, in anembodiment using spring members, the return force may occurautomatically due to the nature of the spring members of amicro-adjustment mechanism; or in a different embodiment, the returnforce may be made by one or more of a second actuator, a third actuator,and/or a fourth actuator.

At 1810, the transfer apparatus determines whether other semiconductordevice die are to be transferred. If no other die are to be transferred,the process ends at 1812. However, if it is determined that more die areto be transferred, the process may begin again at 1802.

Fourth Example Embodiment of a Direct Transfer Apparatus Having aMicro-Adjustment Assembly

FIG. 19A illustrates an isometric view of a two-axis railmicro-adjustment assembly 1900 (hereafter rail assembly 1900) accordingto an embodiment of the present application. Here again, themicro-adjustment mechanism is implemented with the wafer tape conveyancemechanism, for example. However, as indicated above, it is contemplatedthat a similar micro-adjustment mechanism may be adapted to beimplemented with the product substrate conveyance mechanism.Nevertheless, for convenience, FIGS. 19A-19C refer to a rail assembly1900 adapted for adjusting the relative position of the wafer tapecarrying the die to be transferred.

In an embodiment, the rail assembly 1900 may include a substage member1902 (e.g., a plate, a frame, a rigid support structure, etc.) to whicha plurality of rail-guided slide plates (e.g., a first axis slide plate1904 and a second axis slide plate 1906) are slidably attached inseries. The rail-guided slide plates 1904, 1906 may act as supports toconvey the wafer tape carrying semiconductor device die along respectiveaxes responsive to one or more actuations of micro-adjustment actuators1908, 1910, respectively. Further, the rail assembly 1900 may include afirst set of rails 1912 attached to the substage member 1902. The firstset of rails 1912 are positioned to engage slide mechanisms 1914 thatare attached to a side of the first axis slide plate 1904 that faces thesubstage member 1902. The first axis slide plate 1904 may be configuredto slide along a single axis in a direction parallel to the direction ofextension of the first set of rails 1912 when actuated by themicro-adjustment actuator 1908. Although the first set of rails 1912 isdepicted as including two rails, other configurations are contemplatedwhere there may be more than or fewer than two rails.

A second set of rails 1916 may be attached to a side of the first axisslide plate 1904 opposite the side to which the slide mechanisms 1914are attached. The second set of rails 1916 may engage a second set ofslide mechanisms 1918 attached to a side of the second axis slide plate1906 facing the first slide plate 1904. The second axis slide plate 1906may convey the wafer tape carrying semiconductor device die along anaxis parallel to the second set of rails 1916 when actuated by themicro-adjustment actuator 1910. Although FIGS. 19A-19C depict the firstset of rails 1912 and the second set of rails 1916 as perpendicular toone another, it is contemplated that the first set of rails 1912 and thesecond set of rails 1916 may be oriented with respect to each other indifferent orientations than that depicted.

The rail assembly 1900 may include a first stop block 1920 and a secondstop block 1922 to provide a stop point for the edge of the first axisslide plate 1904 and the second axis slide plate 1906, respectively.Moreover, the first stop block 1920 and the second stop block 1922 mayhave secured within respective cavities a compressive bumper 1922, 1924,respectively, against which the plurality of rail-guided slide platesmay abut without damage upon being displaced by micro-adjustmentactuators 1908, 1910. The compressive bumpers 1922, 1924 may be formedof a deformable, resilient material such as rubberized polymer, polymer,rubber, or other suitable material (e.g., soft silicone, sponge, foam,rubber, plastic, etc.). Thus, the compressive bumpers 1922, 1924 mayserve as return members to reset the wafer holder or substrate holder ina neutral position.

FIG. 19B illustrates a side view and FIG. 19C illustrates a bottom viewof the two-axis rail micro-adjustment assembly 1900.

Second Illustrative Example of a Method for Performing Direct TransfersUsing a Direct Transfer Apparatus Having a Micro-Adjustment Assembly

FIG. 20 illustrates an embodiment of a method 2000 for transferring asemiconductor device die using a micro-adjustment mechanism. While anapparatus for transferring die may implement a coarse adjustment thatspans a relatively great distance (which may be, for example, 1 mm, 2mm, etc.) for some die transfers, as discussed above, at times amisalignment may occur, for which the micro-adjustment mechanism may beadvantageous. Furthermore, in some instances, a series of die are to betransferred and though the coarse positional adjustment might be used,due to the relatively close proximity of adjacent die, a coarseadjustment may be impractical. In such a situation, the micro-adjustmentmechanism may be advantageous again.

According to the method 2000, a die transfer sequence may be as follows.In step 2002, the system may set the micro-adjustment mechanism to aneutral position. In step 2004, the system may perform a coarseadjustment by actuating one or more system components such as aconveyance mechanism, for example, to place the components in a transferalignment position. Assuming, the coarse adjustment placed thecomponents satisfactorily in the transfer alignment position, method2000 proceeds with step 2006 by transferring the die. In step 2008, thesystem determines whether there are other die to be transferred in analignment position that can be achieved by using the micro-adjustment.mechanism actuates the micro-adjustment mechanism to shift one or moreof the components to the next transfer alignment position. If thedetermination in step 2008 is positive, the system proceeds to step 2010to actuate the micro-adjustment mechanism to place the components in thenext alignment position. If the determination in step 2008 is negative,the system proceeds to step 2012 to determine whether there are otherdie to be transferred in an alignment position that can be achievedusing a coarse adjustment. If the determination in step 2012 ispositive, then the method reverts to step 2004. If the determination instep 2012 is negative, then the method ends at step 2014.

Note, at step 2006, the system may be requested to transfer more thanone die simultaneously and/or sequentially. In the situation where analignment position exceeds the stroke length available to one or moreneedles of the transfer mechanism, micro-adjustment actuators may beactuated in order to allow the one or more transfers to occur eithersimultaneously when possible or sequentially very rapidly, therebyavoiding a coarse adjustment. Moreover, because a die transfer head mayinclude multiple pins configured in an array that approximately matchesthe pitch between un-transferred die, multiple die may be transferredsimultaneously by actuating two or more of the pins on the die transferhead simultaneously (see FIG. 21, for example).

FIG. 21 illustrates a die transfer head 2102 having multiple pins 2104.In the example shown, the die transfer head 2102 includes 24 pins 2104arranged as two rows of 12 pins at 0.275 mm pitch. The pins 2104 may beconfigured for transferring die according to one or more embodiments ofthe instant application as described above. As shown in FIG. 21, circuitpads 2106 may be configured on a circuit substrate at a predeterminedpitch (e.g., 2.23 mm). The configuration of the known pitch may allowfor multi-pin die transfer using heads having the same (or similar) pinpitch as the predetermined die pitch. For example, a single multi-pindevice die transfer head may transfer two or more device die (transfercombination #1 and #2, respectively) using only a micro-adjustment thatdisplaces the transfer head from position A to position B without acoarse adjustment.

CONCLUSION

Although several embodiments have been described in language specific tostructural features and/or methodological acts, it is to be understoodthat the claims are not necessarily limited to the specific features oracts described. Rather, the specific features and acts are disclosed asillustrative forms of implementing the claimed subject matter.Furthermore, the use of the term “may” herein is used to indicate thepossibility of certain features being used in one or more variousembodiments, but not necessarily in all embodiments.

What is claimed is:
 1. An apparatus for executing a direct transfer of a semiconductor device die disposed on a first substrate to a second substrate, the apparatus comprising: a substrate conveyance mechanism movable in two axes to make primary positional adjustments of the first substrate; a micro-adjustment mechanism coupled with the substrate conveyance mechanism, the micro-adjustment mechanism configured to hold the first substrate and to make secondary positional adjustments on a scale smaller than the primary positional adjustments caused by the substrate conveyance mechanism, and the micro-adjustment mechanism including: a micro-adjustment actuator having a movable distal end, and a substrate holder frame configured to secure the first substrate, and the substrate holder frame being movable via actuation of the distal end of the micro-adjustment actuator; a substrate frame configured to secure the second substrate such that a transfer surface of the second substrate is disposed facing the semiconductor device die disposed on the first substrate; and a transfer mechanism configured to press on the first substrate and transfer the semiconductor device die to the second substrate.
 2. The apparatus according to claim 1, wherein the micro-adjustment mechanism further includes: a wafer support to secure the substrate holder frame, and a return member to reset the substrate holder frame in a neutral position, and wherein the distal end of the micro-adjustment actuator is disposed proximate to the wafer support.
 3. The apparatus according to claim 1, wherein the micro-adjustment actuator is a first micro-adjustment actuator, wherein the micro-adjustment mechanism further includes a second micro-adjustment actuator having a distal end positioned to adjust a position of the substrate holder frame, and wherein the distal end of the first micro-adjustment actuator is positioned to adjust the position of the substrate holder frame in a location displaced by about 90 degrees respective to the distal end of the second micro-adjustment actuator.
 4. The apparatus according to claim 1, wherein the micro-adjustment mechanism is a two-axis rail conveyance mechanism.
 5. The apparatus according to claim 1, wherein the micro-adjustment mechanism further includes a substage plate attached to the substrate conveyance mechanism.
 6. The apparatus according to claim 5, wherein the micro-adjustment mechanism further includes: a first pair of parallel rails attached to the substage plate, the first pair of parallel rails extending in a first direction, a first axis slide plate having a first side opposite a second side thereof, the first axis slide plate being indirectly connected to the substage via the first pair of parallel rails on the first side of the first axis slide plate, a second pair of parallel rails attached to the second side of the first axis slide plate, the second pair of parallel rails extending in a second direction that is transverse to the first direction, and a second axis slide plate indirectly connected to the first axis slide plate via the second pair of parallel rails, the second axis slide plate supporting the substrate holder frame.
 7. The apparatus according to claim 6, wherein the movable distal end of the micro-adjustment actuator is disposed to contact an edge of the first axis slide plate. 